Info - Heat Pumps Scotland

7 April 2022

Alternative To Gas Boilers? Complete Comparison of Heat Pump vs Gas Boiler for UK

There has been a lot of hype in the news recently about whether heat pumps can be a good alternative to gas boilers.

The climate emergency now faced by humankind means we must dramatically reduce the amount of carbon that we are putting into the atmosphere. Governments all over the world are working towards achieving net zero carbon emissions, with the UK Government setting targets to deliver this by 2050 and the Scottish Government going even further to achieve net zero emissions of all greenhouse gases by 2045.

Heat pumps are very efficient at providing heat for our homes whilst at the same time reducing carbon emissions and we must roll out this technology widely across the country if we are to stand a chance of achieving our net zero goals.

The question on everyone’s lips is, “How do heat pumps compare to gas boilers, and can heat pumps be a viable alternative to gas boilers?”

The short answer is that heat pumps are indeed a viable alternative to gas boilers, but let’s look at this in a bit more detail.

First, a reminder of what a heat pump is.

What is a heat pump?

The simplest analogy for a heat pump is the fridge in your kitchen. The fridge removes heat from inside the cooling compartment and dumps that heat into the kitchen via the coils on the back of the appliance.

A heat pump works in the same way, but instead of removing heat from inside of the fridge, it takes the heat from the outside environment (either from the air or, in the case of a ground source heat pump, from the ground). It then concentrates the heat it has collected using a compressor before releasing it inside the house.

It’s a simple technology that people have been using for years, but in Scotland we have been slow to apply it to heating our homes.

Practical considerations

We all have a lot on our plate, with family, work and other commitments vying for our time. We want our heating systems to “just work”, providing warmth without any fuss, so we can get on with our busy lives.

There has been good reason in the past for people to heat their homes using fossil fuels, not least the low running costs of a gas boiler using mains gas. The economics and convenience of such systems have resulted in 80% of domestic properties in the UK being heated with mains gas.

If you are considering a move towards more environmentally friendly alternatives, you are probably wondering whether a heat pump can deliver the same convenience, warmth and affordability as a gas boiler.

Let’s look at some of the most common questions people have about heat pumps.

Can a heat pump heat a whole house?

The short answer is yes, a heat pump can heat a whole house.

Heat pump systems must be carefully designed and consider the specifics of the house they will be heating. For example:

Is the house well insulated?
What is the preferred temperature of the rooms being heated?
What is the outside temperature?
How much outdoor space is available?

All these things will influence the size of the heat pump required, and whether an air source, ground source or water source system would best suit.

If there is plenty of space available to bury the collector pipe, perhaps ground source heating is worth looking into, or if there is a suitable body of water close by, a water source might offer the best efficiency.

In any case, a properly designed heat pump system will have no trouble heating a whole house.

Is it cheaper to run a heat pump all the time?

Some people like to be able to turn their heating on and off quickly, for example so they can open the windows and let in all that lovely fresh air without wasting money heating the outside of their property.

A common question about heat pumps is whether they need to run continuously to be effective. If that was the case, it would put off the fresh air fiends out there because they would have visions of living in a hermetically sealed box with no access to fresh air.

In general, it is not cheaper to run your heat pump all the time. Most people find that setting their heat pump to a lower temperature overnight saves them money on running costs. Likewise, not running your heat pump while you are out at work, or away for the weekend will reduce running costs, too.

Something to consider, particularly if your property is relatively modern and airtight, is a heat recovery and ventilation system. The system will allow your home to receive fresh air without having to open your windows. Instead, fresh air is blown into your house to provide ventilation and the incoming air is warmed using exhaust air, which saves on heating bills without compromising air quality. Perfect for the fresh air fiends out there.

At what temperature do heat pumps become ineffective?

The short answer to this question is typically at temperatures below those experienced in Scotland (heat pumps can operate at temperatures as low as -25°C).

This is perhaps the wrong question to be asking though. If you have a heat pump that can operate in outdoor temperatures as low as -25°C, you’ll be fine pretty much anywhere in the UK on any day of the year.

Perhaps what you should be asking though is whether the particular model of heat pump that you will be using is effective at those very low temperatures.

Not all heat pumps can operate in such cold environments, so it’s important to check that yours will if you need it to.

Something else to think about is the efficiency of the heat pump system, which isn’t only related to the outside temperature, but the difference between the indoor and outdoor temperatures. If you are used to keeping your home at 35°C to be comfortable, you might find your heat pump never quite gets you there.

The wider the gap between the outside temperature and the desired indoor temperature, the harder your heat pump will have to work to maintain that indoor temperature. The harder your heat pump has to work, the less efficient it will be.

This is why low temperature underfloor heating is a good match for a heat pump – the large surface area allows for sufficient heat transfer without the need for high temperature radiators. This in turn allows the difference between the inside and outside temperatures to be kept small, resulting in a more efficient heat pump system.

Heat pump efficiency

I just touched on the issue of efficiency, and it is worth sticking with this topic for a moment.

How is heat pump efficiency measured?

The main statistic that is used to measure the efficiency of a heat pump is the Coefficient of Performance (COP).

What is COP?

COP, simply put, is the ratio of the amount of electrical energy required to operate a heat pump to the amount of heat energy it produces.

So, for a heat pump that produces 4 units of heat energy for each unit of electrical energy consumed, the COP would be 4.

What is a good COP for a heat pump?

A COP of 4 is excellent and an expected range for heat pumps in the UK would be between 2.5 and 3.5.

Heat pump carbon savings

The top end of the COP range equates to an efficiency of 350% for a heat pump, which is a lot better than even the most efficient, modern condensing boiler, which can only manage 90% or so efficiency.

There is really no comparison. Plus, when you take into account the fact that the electricity grid is becoming greener all the time, with renewable energy becoming an ever larger proportion of the electricity generation mix, the carbon savings of using a heat pump compared to a gas boiler are huge.

If you can generate your own electricity using renewable solar PV, wind turbines or something else, then that brings even greater carbon savings – possibly even going beyond net zero.

Financial considerations

In the previous section, I explained how a heat pump can provide the same convenience and comfort as a gas boiler. The all-important issue of cost is next under the microscope, and this can be broken down into installation and running costs.

Zero VAT for heat pumps

The Chancellor’s announcement that rate of VAT payable for heat pumps would be zero for the next five years is surely a welcome fillip to the sector, but heat pumps are still a relatively expensive option in terms of up-front installation costs compared to more traditional options such as the gas boiler.

Boiler Upgrade Scheme (BUS scheme)

The Boiler Upgrade Scheme only applies to England and Wales. It aims to encourage the use of heat pumps and biomass boilers for space and water heating in certain properties.

Hopefully a similar scheme will be announced for Scotland and Northern Ireland that can replace the Renewable Heat Incentive (RHI), which ended on 31 March 2022 after a one year extension to its original lifetime.

Heat pump installation costs

Installation costs of a heat pump will vary according to the type and size of heat pump required. For a 2-3 bedroom house, they typically range from £8,000 for a medium-sized air source heat pump, to £20,000-£30,000 for a ground source heat pump.

The reason for the large difference in price is largely due to the substantial groundworks required for a ground source heat pump. The ground collector either has to be buried in trenches, or installed in a borehole, which requires specialist borehole drilling machinery, which is also expensive.

Octopus Energy are spearheading a move to bring down the costs of installation of heat pumps by optimising the installation process. They are also working with heat pump manufacturers to bring down the cost of the units themselves. Fingers crossed they mange to do this and, in the process, make heat pumps available to a wider market.

Heat pump running costs

The running costs of heat pumps depend mainly on the cost of electricity because they only need a service once a year and this is not particularly expensive (approximately £200 plus parts).

With the energy crisis grabbing headlines recently, you can’t fail to have noticed that the cost of electricity has gone up, a lot.

But so has the cost of gas, which means the scales haven’t necessarily been tipped in favour of fossil fuels.

Let’s take a look at the cost of running a heat pump for the 2-3 bedroom property we used as an example above. Before the price rises, the cost of heating a home like this would come in at just under £1,000 per year, which is around £200 cheaper than an equivalent gas boiler driven system.

As a result of the price cap rises, electricity has gone up around 72% on average, but gas has risen even more (by around 84% on average), which means that the savings likely to result from using a heat pump compared with a gas boiler are even greater.

But I’ve heard that heat pumps are worse than gas boilers

Let’s bust some heat pump myths!

If you’ve spent time researching heat pumps on the internet, you will have come across stories of people paying extortionate amounts for their electricity since installing a heat pump. Or perhaps even worse stories of cold homes and unreliable equipment.

What many of these stories have in common is that the heat pumps in question have been incorrectly designed and/or installed.

Normally, those complaining online of an unsatisfactory experience with their heat pump are met with responses from lots of satisfied heat pump customers offering advice and sharing their more positive experiences.

One such positive experience was shared online at the Home Farm website, as follows.

“We have a 4 bedroom house and had an ASHP installed in September 2021. Our heat pump is a 12kW Vaillant. The cost of heating and hot water from 7 November – 7 December 2021 was £144. The heating is on from 06:00 hours to 20:30 with a 2 hour break in the middle. The hot water is set on for a 12 hour period. We live in a frost hollow in eastern Scotland and have gone through two storms in the last two weeks and overnight temperatures hovering at around zero for the last fortnight. Our home is timber-framed and reasonably well insulated but the bedrooms upstairs have 30 years old velux windows which are not particularly well insulated. We only upsized the downstairs radiators. Despite all of this we find we are warm and cosy.”

This was in response to someone posting a comment about their air source heating costing £6,000 per year to run. Such high running costs are not the typical experience but give credence to the critics and naysayers who wrongly spread rumours about heat pumps not being capable of heating houses efficiently in the UK.

The unfortunate truth is that there are companies out there installing heat pumps who shouldn’t be. Buyer beware is good advice and if you can, it’s a good idea to educate yourself on system design basics so you know what questions to ask.

Failing that, make sure you get good recommendations and always follow up on references before going with an installer.

Summary

Heat pumps are a good alternative to gas boilers for your domestic hot water and space heating needs.

Heat pumps are a very effective way to reduce your carbon footprint and save money on your heating bills in the long run, provided they are correctly designed and installed.

Are heat pumps worth the money?

Yes. They cost more up front than gas boilers, but the installation costs are mitigated by their zero VAT rating and the availability (in England and Wales) of financial assistance in the guise of the Boiler Upgrade Scheme (BUS).

Heat pumps are cheaper to run across time thanks to their superior efficiency.

Are heat pumps a good alternative to gas boilers? The Key points

Heat pumps are a good alternative to gas boilers.
A heat pump can heat a whole house.
It is not cheaper to run a heat pump all the time.
Heat pumps are effective down to temperatures as low as -25°C.
Heat pumps save carbon emissions vs gas boilers.
Installation costs of heat pumps are larger than for gas boilers but financial incentives are available to help with the costs.
Heat pump running costs are normally lower than gas boilers, provided they are properly designed and installed.

20 March 2022

How Long Do Heat Pumps Last? The Answer is Astounding!

One of the key things people need to know when working out if a heat pump is worth investing in is how long do heat pumps last.

Heat pump technology is not something that everybody is familiar with, so it’s only natural that this question arises quite frequently. In this article, we’ll try to address the key concerns that you might have in relation to the longevity of your heat pump and look at the factors that affect this.

Modern heat pumps are very reliable, so it’s our hope that by the end of this article, you’ll have more confidence in investing in this tried and tested technology.

How long should heat pumps last?

According to the energy saving trust, provided it is well maintained and operated, a heat pump can be expected to operate properly for over 20 years. Heat pumps have come a long way since the early days and like any technology the reliability and efficiency have just got better and better as time has gone on.

Indeed, these days it is not uncommon for heat pump manufacturers to offer 10-year warranties, which cover parts and labour. Now that’s peace of mind.

If you’re concerned about how long your heat pump is going to last, you may have heard some stories from the 1970s or 1980s of shorter life spans. But even back then, you could comfortably expect 10 to 15 years of reliable service from your heat pump.

Perhaps a valid concern might be if you live on the coast and are worried that high levels of salt in the atmosphere, which could cause corrosion of your heat pump. Coastal conditions are not kind to mechanical systems, but if you live on the coast you will already know this, most likely from the premature appearance of rust on your car.

It’s worth having a conversation with your heat pump installer if you have any concerns about the likely impact of the weather and local conditions on your heat pump’s longevity. They will be able to advise you and, if they are a well-established firm, might even have customers who live in a similar location that installed their heat pump many years ago. If that’s the case, they will be able to point to real life examples of how heat pumps perform in your part of the world.

Factors determining how long do heat pumps last

As with any complex machine, there are lots of factors that can influence their working life span. We’ve already mentioned some of them above but let’s do a deep dive into everything that you should be aware of, so you know what to keep in mind.

Type of heat pump

If you have spent any time at all on this website, you’ll already know that there are three major types of heat pump, classified according to where they obtain their heat from. The different categories of heat pump are air source, ground source and water source.

The most popular type of heat pump to install in the domestic and business setting is overwhelmingly air source. This is because air source heat pumps are simpler and cheaper to install than ground source and water source heat pumps, mainly because they are a single, self-contained unit that sits outside your building.

Contrast this with other types of heat pump, which require the heat collector to be installed underground or in the bottom of a water body, and you can see how Installation costs can quickly ramp up.

Simply digging the trench for a ground source heat pump can take several days, causes a lot of disruption and mess, and adds to the overall cost of installation. If you intend to use borehole for a vertical ground loop, there’s the added complication of specialist drilling equipment and the risks around encountering unexpected ground conditions that could increase the cost of drilling.

Usage Patterns

Using a heat pump less often will obviously cause less wear and tear on moving parts, which means its component parts will last longer.

However, the paradox here is that the advice for running your heat pump efficiently is to let it run continuously, even if you pop out to the shops for an hour or two.

Doing anything that makes your heat pump work excessively hard is likely to reduce its lifespan, or at least the lifespan of certain components. You might want to make sure that you are not turning it on and off too frequently, although this is likely to have a relatively minor impact on the lifespan of your heat pump, so the most important thing is to make sure it works for you and your lifestyle.

Location and Climate

If you live in a relatively temperate climate, such as here in Scotland, your heat pump won’t need to work as hard as it would in more extreme climates, such as Alaska or Canada.

When temperatures plummet, the larger difference between the outside temperature and the desired inside temperature means that the heat pump has to work harder to maintain the indoor temperature.

Not only does this mean that the heat pump works slightly less efficiently, but also induces greater wear entire on the component parts, which can reduce the lifespan of the heat pump itself. Or at the very least will increase the amount of maintenance required and frequency of part replacement.

Local Conditions

It’s important to make sure that your heat pump is installed properly. An important consideration is the correct location for your heat pump.

Allowing proper circulation of air around the heat pump is extremely important, as is ensuring it is not a risk from trees or other plants dropping leaves or even dead branches on top of it. Overlooking any of these factors could certainly reduce the lifespan of your heat pump.

Stress to the unit caused by insufficient air circulation is going to make it work too hard and possibly fail prematurely. And clearly evident branch lands on top of it, that could be very bad for its continuing functioning also.

Maintenance And Servicing

It’s extremely important that you maintain and service your heat pump regularly. A stitch in time saves nine as they say, and that is true of any mechanical device particularly a heat pump.

A poorly maintained unit won’t last as long as one that has been well maintained and cared for. Service intervals on heat pumps vary, but once a year is a good rule of thumb.

Ensuring fan blades are kept clean and bearings are greased just makes good sense and will help your heat pump to last longer.

Signs Your Heat Pump Might Need Replacing

No matter how well you look after your heat pump, it will of course need to be replaced at some point. Nothing lasts forever, but how will you know when your heat pump might need major repair work or even complete replacement?

Refrigerant leakages

Leaking refrigerant is a tell-tale sign that your heat pump requires urgent maintenance. Refrigerants are greenhouse gases, so it is no good to have leaks which will add to ongoing global warming.

Your heat pump won’t work properly either without sufficient refrigerant, so if you spot a refrigerant leak it’s important to get it fixed as soon as possible.

Every time you recharge the refrigerant, it will cost you for the refrigerant itself as well as callouts and labour costs. This is not a job you can do yourself and will require a certified technician. If you find yourself calling out a technician regularly, it might be time to invest in a new heat pump.

Reduced efficiency and large electricity bills

As you heat pump gets older, it is normal for its efficiency to tail off somewhat. The less efficient your heat pump gets, the more you are going to spend on electricity.

If regular maintenance and or repair fails to get your heat pump operating efficiently again and doesn’t bring your electricity bills down, it could be time to get a new heat pump.

Compressor failure

The compressor is such an important component and one that does a lot of the donkey work in your heat pump, that even with regular maintenance it can go kaput.

If your heat pump is come to the end of his warranty and the compressor fails, you’ll need to weigh up your options carefully. However, the most economic thing to do might well be to buy a new heat pump instead of replacing the compressor, which is a very expensive component.

Tips On Maximising Your Heat Pumps Lifespan

it’s not rocket science to follow best practice for maintaining your heat pump and therefore maximising its lifespan. Most of the steps you would need to take part common sense.

Some steps require a heat pump technician, but there are some you can do yourself.

Let’s take a look at some of the best practices you should follow.

Get your heat pump serviced every year
Clean the air filters approximately once a month
Replace the air filters three or four times a year
Make sure the refrigerant is kept topped up
If you live in a cold region and ice forms on the outdoor unit, clear this away
Give the coils a wipe to keep them clean

Use a Programmable Thermostat

Programmable thermostats can work very well in harmony with your heat pump. They allow you to control how your heat pump runs, automatically switching it off while you’re out of work for example turning it on in time for your return home.

This means it’s only running when necessary and can reduce wear and tear ensuring your unit last as long as possible.

Summary

These days modern heat pumps should provide you with loyal, reliable service for 20 years or more, provided you take care of them.

If you ensure your heat pump is properly installed, regularly maintained and serviced, you could see its lifespan extended well beyond what you might expect.

Follow the tips and advice above and you’ll get the most out of your unit in the long run.

If you enjoyed this article, why not read more about heat pumps in our popular article about how heat pumps work, or how to find a heat pump installer?

11 March 2022

Best heat pump thermostat settings for Scotland’s climate

A question we are often asked here at Heat Pumps Scotland is what is the best heat pump thermostat settings to use for the Scottish climate?

What most people seem to try is randomly adjusting their thermostat in a process of trial and error until they happen upon the best setting for their home. The problem with doing this however is that you can waste a lot of time and energy searching for the right place on the dial. Also, unless you keep a close eye on the efficiency of your heat pump system whilst doing this, all you’re really doing is yo-yoing around some notion of your ideal temperature and probably ending up with a somewhat uncomfortable home environment with little or no gain in efficiency and cost.

What is the most efficient setting for a heat pump?

What you should try to do when finding the best heat pump thermostat setting is to get the perfect balance between comfort and energy efficiency, which is different for everyone. A well-off person who likes a very warm home might favour a setting which keeps their home lovely and warm but is quite expensive to run. However, a more environmentally conscious person, or someone who is on a tight budget, might be willing to turn the thermostat right down in order to save the planet and or their wallet, especially if they don’t mind the cold, or perhaps even prefer their home to be on the cool side.

A good rule of thumb is to keep your heat pump thermostat set to between 20 and 25°C throughout the winter.

What temperature should I set my heat pump thermostat to?

Although in Scotland most people will use their heat pump for heating pretty much all the time, it is possible to use it for cooling your home during the summer. If you have a system that allows you to do this, you will need to adjust your thermostat to the optimal setting for winter or summer depending on the season.

Best temperature to set a heat pump to in winter

The best temperature to set your heat pump to in winter is around 20°C. Turning the temperature down a bit during the winter months can save you some decent money here in Scotland. The only exception to this would be if you have an auxiliary heat system that kicks in during very cold spells. If you have a backup gas boiler or oil fired boiler, which takes over when temperatures are at their coldest and when your heat pump would struggle, it might make perfect economic sense to keep the temperature setting for your heat pump higher and rely on this auxiliary heating system to fire up when needed.

One thing I would recommend though is turning the stat down while you sleep at night. The same could be true if you’re not actually in the home, for example during the hours you are out at work. There is little point hitting an entire house when you’re tucked up safe and cosy in your bedroom or else not even there at all.

Best temperature to set your heat pump during the summer

Let’s face it, in Scotland you’re very unlikely to need your heat pump to provide cooling, even during the hottest summer days. But if you have such a unit installed and find occasion to use it, it would be advisable not to set it any lower than 25°C.

Again, think about how you could make best use of the system, perhaps by turning it off at night and when you are out.

What can affect your heat pump setting?

Your home is likely to be fairly unique in terms of his heating and cooling characteristics. Even houses built right next door to each other can have quite stark differences in the level of insulation they have, how much ventilation is available, not to mention the preferences of the occupants.

For example, I know someone who lives at the top of the hill in a small village. They never had any problems with a lack of ventilation because the breeze at the top of the hill provides plenty of natural cooling. It also has the benefit of minimising the nuisance caused by those pesky Scottish midges!

Just a few hundred metres down the hill however, my other friend has a house which is quite sheltered and is very little breeze resulting in quite sticky hot temperatures in his home during very hot days. We also have a hard time of things on summer evenings when the midges come out and attack everyone who is in the garden, which has ruined a few good barbecues.

Outdoor temperature

If you can get away with setting your heat pump to a similar temperature to that outside, you’ll find it will run very efficiently and not consume a lot of energy. As temperatures plunge during the winter time, heat pump efficiency also goes down.

A large difference between the outside and inside temperatures will make your heat pump work harder and consume more electrical energy. This in turn will cost you more money, not to mention the fact it is bad for the environment.

Humidity level

In these mild Scottish climes, humidity can tend to creep up to uncomfortable levels. I found this to be particularly true in forested areas, where moisture from the evapotranspiration of trees is compounded by the shelter afforded from the breeze by woodland vegetation. This can make summer days where the Mercury hasn’t risen all that far feel sticky and oppressive.

Most people find that humidity levels between 30 and 60% feel comfortable. It’s best to keep your homes humidity levels somewhere in the middle of that range.

During the winter months, when condensation can become a problem indoors, it’s advisable to keep humidity levels towards the lower end of the range mentioned above. The dryer the atmosphere, the less chance of condensation.

If condensation is allowed to form through a combination of excessive humidity and humid air coming into contact with cold surfaces, this can become a real concern both for the integrity of your building and for the health of its occupants. Condensation can cause the buildup of mould, which poses a threat to human health.

One way to deal with this is to open the windows and allow the human air to escape, but heating your home with the windows open, even just on vent, will make your heating system much less efficient and expensive to run.

Sensible settings for your heat pump while you’re out

There is no need to have your heat pump working hard while you’re not in the building. So, best practice is to turn the temperature on the thermostat down during the wintertime if you’re not in.

Likewise, if you are using your heat pump for cooling, during the summer allow the thermostat to be notched up a little while you are not at home.

These practices will allow the heat pump to not work as hard when it doesn’t need to, which will save you money and energy.

Run your heat pump on a lower power setting overnight

When you go to sleep at night, it makes sense to turn the temperature down on your heat pump during the winter, say to 20°C. During the summer, if using it for cooling, allow the temperature to creep up a little, say to 25°C.

When you’re asleep, your metabolism slows down and your body naturally generates less heat. This means that you can get away with it being warmer during the summer without breaking into a sweat. And during the winter, even though your body is naturally generating less heat while you sleep, it’s likely you’ve got your thermals on and are wrapped up in a nice thick duvet.

So take advantage of these times when you don’t actually need your heat pump to be running flat-out, and let it take a break, conserving energy and costing you less.

How to maximise your heat pump’s efficiency

We’ve covered basic principles of how to make sure your heat pump is running as efficiently as possible. Let’s look at some specific steps that you can take to maximise that efficiency.

Regular heat pump maintenance

This is often overlooked by heat pump consumers, but it is incredibly important to keep your heat pump well-maintained. Even simply cleaning the important components regularly, such as the fan blades, can help to prevent the efficiency of your heat pump reducing over time. It can also have the added benefit of reducing the noise from the fan on your unit.

Other things that will be taken care of through proper maintenance include regassing the refrigerant so that it is always that the correct pressure and there is sufficient refrigerant in the system. Also, cleaning air filters regularly will obviously ease the flow of air through the unit, which for obvious reasons will help efficiency. Removal of a buildup of ice, which can often happen during the winter, will also improve the efficiency of an outdoor heat pump unit.

Improving Insulation and making sure your building is airtight

This is the elephant in the room and attention needs to be drawn to it. If your house is poorly insulated, you might find your heat pump struggling to keep your house warm. Likewise if you have cracks allowing drafts to blow through your house this will cause your heat pump difficulty in maintaining a comfortable temperature inside.

The only way to fix this is to retrofit proper Insulation, either rock wool, insulation board or whatever suits your circumstances. A tube of mastic can also work wonders for sealing up any cracks through which drafts are blowing, especially important in windy areas of Scotland such as on the coasts and particularly the islands.

Use of curtains

It can seem a little obvious and perhaps low-tech, but closing the curtains to prevent sunlight streaming in can really help to keep your house cool, particularly if the windows are south facing.

Likewise, curtains closed at night during the winter can help to minimise drafts and improve heat retention around windows in your home. I’ve also seen curtains drawn across front doors and even interior doors, which also seem remarkably effective in keeping drafts out and improving heat retention in homes.

Summary of best heat pump thermostat settings

So in summary, the best way to ensure your heat pump is running as efficiently as possible is to keep the temperature on your thermostat as close as possible to the temperature outside. This means your heat pump doesn’t have to work hard to maintain a large temperature difference.

Adding the useful tips provided above to ensure heat loss is minimised through the use of curtains, good Insulation and proper maintenance will ensure your heat pump operates as efficiently as possible for many years to come.

It’s all about finding the right balance for you – turning your heat pump down just a few degrees can make a huge difference to efficiency, which is great provided it doesn’t cause you too much discomfort. This decision is very personal and varies from household to household.

Whatever you do, though, make sure you get professional advice to ensure your heat pump system is appropriately designed and fitted so that it performs well for your particular preferences, type of home and how you live your life.

24 February 2022

Alternative Heating Systems – Efficient, Green Solutions

The current global energy crisis has forced many people in the UK to assess alternative heating systems for their homes.

Even before gas, oil and electricity prices began to skyrocket, many people were investigating alternative heating as a means of reducing their carbon footprint and at the same time save some money.

Government incentives such as the renewable heat incentive (RHI) have seen an increase in the number of people expressing an interest in heat pump technology, solar power and even wind power. But what are the pros and cons of investing in alternative heating systems, and what even are the alternatives? Read on to find out more.

What are alternative methods for heating?

There are many alternatives available for heating your home and providing hot water, from the traditional options such as gas or oil boilers, through wood-burning stoves, to what many people consider truly alternative heating such as heat pumps, solar PV or biomass boilers. There are even hybrid heat pump systems that incorporate renewable heat pump technology with fossil fuel boilers.

These different types of heating fall into two broad categories:

“Traditional” fossil fuel heating; and
“Alternative” renewable heating

There is some grey area in the middle, for example wood-burning stoves do not utilise fossil fuels to provide heat, but depending on whether the wood is sourced from sustainable forestry, how far the wood has to travel from where it is harvested to where it is burnt and whether it has been kiln dried prior to sale, are all factors that can bump up the overall carbon footprint of your wood-burning stove.

Let’s take a look at some of the different methods for heating your home and consider the pros and cons of each alternative heating method.

Traditional heating systems

Traditional heating systems all have the advantage of using well established and proven technology.

Many are based on fossil fuel, which is very bad from an environmental point of view. However, sometimes there is simply no alternative, either for financial reasons or because alternative heating technologies are unsuited to the demands of a harsh climate or particular user needs.

Mains gas

By far the most popular form of heating in the UK, mains gas has earned its number one position at the top of the user charts because of its convenience and affordability. Despite contributing to global warming, many people find that mains gas is just too convenient and too cheap an option to pass up.

At the time of writing the average cost per kilowatt hour of gas in the UK is approximately 3.8p. This is less than a quarter of the cost of electricity. It is very easy to see why this is such a popular choice for many people.

Another great advantage that gas has in his favour is its convenience. At the flick of a switch or the turn of a dial, you can enjoy instant heat. This benefit was drilled home to millions of people during the “cookability” advertising campaign run by British Gas in the 1980s. The cookability adverts featured Noel Edmonds interviewing housewives about how gas was such a good fuel for cooking. If you’re of a certain vintage you may remember these adverts, but just in case you’ve forgotten or are too young to have seen these the first time around, I have embedded an example below.

It is not all positive for mains gas, however, because as I said above it is a greenhouse gas and therefore contributes to global warming.

The current tensions in Ukraine are also highlighting concerns about security of supply and potential increases in price. Although around half of the gas used in the UK comes from the North Sea and a further third comes from Norway, the UK could still be badly affected if Russian gas becomes more scarce.

This is because countries that currently buy a lot of Russian gas would quickly have to find alternative supplies, and would end up competing with the UK for those supplies. This could cause sharp rises in price, which is a potential downside for mains gas.

Mains gas advantages

Low cost per kilowatt hour.
Convenience.
Easily controllable.
Amazing cookability!

Mains gas disadvantages

Fossil fuel – contributes to climate change.
Prices could skyrocket if Russia turns off the tap (or supply is reduced some other way).

LPG gas

If you want to use gas and are not on the mains gas grid, your best bet is to heat your home using an LPG boiler.

LPG stands for liquid petroleum gas. If your needs are modest, you can purchase LPG gas in 47 kg bottles. Each bottle will typically last between six months and a year if you are using it purely for cooking, but if you want to use LPG to heat your home, you’ll need a much bigger tank.

Commonly, a large LPG tank will be provided by your gas supplier, who will normally retain ownership and you will pay a rental fee for the use of the tank. You might be locked into a contract with this gas supplier as well, which might be seen as a downside leaving you with a lack of choice and options if the supplier pushes up prices.

LPG is a fossil fuel, so this is not a particularly green choice. It could also be subject to price rises and the vagaries of the international gas market. The price of LPG gas per kilowatt hour at the time of writing is around 8p, which is about twice the price of mains gas.

LPG gas advantages

Convenient
Despite being more expensive than mains gas, still good value.
Easily controllable.
Can be used for cooking as well as heating (there’s that cookability factor again!)

LPG gas disadvantages

More expensive than mains gas.
Fossil fuel – contributes to climate change
Subject to the same potential price increases as mains gas

Oil fired boiler

Oil fired central heating is another popular choice for people who live off the gas grid. Over 1 million homes in the UK use oil heating, so it’s a popular choice if you’re not on the gas grid.

Oil fired combi boilers are very efficient these days and can achieve over 90% efficiency. Oil tends to be cheaper per kilowatt hour than LPG but oil boilers are slightly more expensive to install than equivalent LPG boilers.

Like LPG, you’ll need a tank to store the fuel. Oil can be delivered by tanker to your property and you can come to an arrangement with your supplier to automatically top up your tank as and when it’s needed. This is normally done by installing sensing equipment in your tank, which communicates with the oil depot to alert them when a top-up is required.

Even if you don’t have sensor on your tank, some suppliers will simply agree to top up your tank whenever they are passing, thereby making sure that you never run out.

Oil is a slightly smellier fuel than LPG for mains gas, but this is rarely much of an issue because your oil tank is generally well away from your house and emissions from the boiler itself are fairly innocuous.

In fact, a heating engineer I know told me that the emissions from an oil fired boiler in the UK have to contain lower levels of carbon monoxide than those that would trigger a carbon monoxide alarm to go off. I have in fact checked this but doubt that he would make that claim lightly.

Oil fired boiler advantages

Low cost per kilowatt hour compared to LPG
Convenient and easily controllable
Modern oil fired boilers are extremely quiet and efficient
Oil fired boilers give very strong performance during cold winters

Oil fired boiler disadvantages

Oil tank can be smelly
Greater the potential for localised pollution due to oil spills
Installation of the boiler more expensive than LPG gas boiler
Storage tank more expensive than LPG storage tank
Fossil fuel – contributes to global warming

Electric heating

Electric heating is a viable way to heat your home if you are not on the mains gas grid, but you really need to think about whether it is suitable for your home before taking the plunge because unless you are careful this can turn out to be quite an expensive option.

Even before the current energy crisis, electric heating was significantly more expensive to run than mains gas heating. With the cost of electricity on the rise, the economics are not working in its favour.

One of the key advantages of electric heating is that it’s a very clean form of heating. There are no emissions from a flue, in contrast to gas and oil boilers, which means you don’t need to think so hard about where to position your boiler or worry about siting it away from windows.

Electricity can also be considered greener as a form of heating when compared to fossil fuel alternatives such as oil and gas, particularly if you are on a green tariff which uses electricity generated from renewables.

The relatively high cost of electric heating can also be mitigated by using cheaper rate electricity. Economy 7 allows you to use electricity at a cheaper rate during a seven-hour period overnight and Economy 10 does the same thing but with an additional three hour window in the afternoon.

In order to take full advantage of the Economy 7 and Economy 10 tariffs, you need to have night storage heaters. Storage heaters contain ceramic, thermal energy absorbing blocks, which store the heat generated overnight and release it gradually during the day.

The rate of heating provided by storage heaters is controlled using adjustable vents which allow more warm air to flow into the room when opened. Some models of storage heater also come with fans to help distribute the heat around the room.

Modern storage heaters also come with all the bells and whistles that we have all come to expect, such as controllability via smart phone controls, automatic timers and thermostats. One of the criticisms of storage heaters in the past was that they were unable to store sufficient heat to keep your home warm throughout the day.

This meant that they would run out of heat energy by evening, just when you wanted your house to be at its cosiest. More modern designs that are cleverer about how the heat is released and innovations in technology that allow more heat to be retained by the ceramic blocks have improved performance so that this is less of an issue these days.

Advantages of electric storage heating

Clean technology
Cheaper to install than gas or oil boilers
A low maintenance requirement
Electric heating is available in areas not served by mains gas
Using green electricity tariffs means electric heating contributes less to climate change
Economy 7 and Economy 10 tariffs allow for maximum efficiency

Disadvantages of electric heating

Relatively expensive when compared to mains gas
Not as controllable as fossil fuel alternatives
Storage heaters can run out of heat towards the end of the day meaning your house might be cooler in the evenings

Alternative Heating Systems

There are many alternative heating systems on the market these days, which can make deciding on the right one for you confusing and difficult.

The UK government is looking to phase out all gas and oil fired boilers for new build homes by 2025. This will help us to achieve our climate change targets but doesn’t really go far enough because it doesn’t tackle our existing housing stock. If we are really serious about tackling climate change, we need to get busy retrofitting existing homes with renewable heating.

But why go to all the expense and disruption involved in replacing your heating system? Well, apart from the warm glow (pun intended) you will get from knowing you’re doing the right thing for the planet, you might be pleasantly surprised to discover that you can save money and have a more convenient, controllable heating system.

The government extended the renewable heat incentive (RHI) to support homeowners who wish to install renewable heating. Given the ambitious targets set, it seems likely that some form of incentive will be available for some time to come.

So what are the options? Let’s take a look at a few of the more popular renewable heating systems available today.

Air source heat pumps

Air source heat pumps make use of the ambient heat available outside to heat your home. It’s difficult to believe, especially in Scotland, but even during the winter there is sufficient heat available in the great outdoors to operate an air source heat pump effectively.

All heat pumps use the refrigeration cycle – a well established scientific process – to gather heat, concentrate that heat and then distribute it throughout the home. They are essentially air conditioning units in reverse.

Air source heat pumps come in the form of a discrete box, which sits outside your home. They can be installed in just a few days and with minimal disruption. Once installed, they run reliably and with very little maintenance being required. It’s a good idea to clean them every now and again and to ensure they get a service every year, however you shouldn’t need to spend very much money repairing or maintaining them.

Air source heat pumps are a very clean way to heat your home because there are no emissions, in contrast to an oil or gas boiler, the exhaust gases from which need to be ejected via the flue.

Because they move heat rather than generate heat directly using electricity, they are far more efficient than traditional electric heating, typically having a coefficient of performance of between three and four. A coefficient of performance of 4 means that for every unit of electrical energy used by the heat pump, 4 units of heat energy is generated.

Such high-efficiency is the reason that heat pumps are classed as renewable energy, which means that they qualify for the government incentives mentioned above.

One important thing that is sometimes glossed over by people keen to promote heat pumps, is the fact that you need to have a well insulated home for them to operate efficiently. Heat pumps operate at lower temperatures than traditional boilers, which can simply be turned up higher in a draughty old house during the winter. If you try to do the same thing with a heat pump, you could find that your electricity bills are rather large, you might even find that your house is a bit cooler than you would prefer.

Air source heat pump advantages

Clean form of heating with zero emissions at point of use
Classified as renewable – contributes less to climate change
Qualifies for the renewable heat incentive (RHI) payment scheme
Relatively cheap installation cost
Low running and maintenance costs

Air source heat pump disadvantages

Appearance of some models not aesthetically pleasing
Could require planning permission in some circumstances
Good insulation is required as a prerequisite, which can be expensive if it needs to be retrofitted
Noise – certain models have been known to be a little noisy, which can cause problems if the unit is installed to close to a bedroom window, for example.

Ground source heat pumps

Ground source heat pumps operate on the same basic principle as air source heat pumps i.e. they absorb heat from outside the building and transfer it to the inside using the principles of the refrigeration cycle.

A refrigerant is circulated around the system and absorbs heat in the evaporator pipework. In the case of a ground source heat pump, this is called the ground loop and is buried underground instead of simply being placed outside your house with a fan blowing air across it.

Once the heat has been collected, it passes through a compressor and then onto the condenser, which rejects the heat and makes it available for the heat distribution system chosen by the householder.

Popular forms of heat distribution include underfloor heating and low-temperature radiators, both of which are ideally suited to the task of warming the home as part of a heat pump system. This is because they both have a very large surface area across which heat transfer can take place, which is necessary due to the low operating temperatures of heat pump systems.

It is important to bear in mind the type of heat distribution that your heat pump system will need, because retrofit of underfloor heating, or replacement of your existing radiators with low-temperature radiators is likely to be very disruptive and expensive.

Installation costs of ground source heat pumps are higher than those for air source heat pumps because of the ground works required. The ground loop has to be buried in trenches in your garden. Again, this is very disruptive and obviously more expensive than simply placing an air source heat pump unit at the side of your house.

It also requires that you have plenty of space available because the ground loop can be quite large. For this reason, ground source heat pumps are not well suited to all properties. On the plus side, more consistent temperatures below ground often mean the ground source heat pumps can operate more efficiently, which makes for lower running costs.

If your heart is set on having a ground source heat pump but you don’t have lots of space outside your house, it may be possible to drill a deep borehole instead of a shallow trench to accommodate the ground loop. If this is what you want to do, it’s important that you get good advice because drilling boreholes can be expensive. The exact cost will depend on ground conditions that are encountered by the drillers but you could easily spend £5000 for a single borehole and chances are you will need more than one borehole to drive your heat pump.

Ground source heat pump advantages

Normally more efficient and cheaper to run than an air source heat pump
No fan blowing air across your heat pump pipework outside your bedroom window
Renewable form of heating – contributes less to climate change
No flue gases generated

Ground source heat pump disadvantages

Ground loop installation is very disruptive
Installation costs tend to be quite high
Insulation to a high standard is a prerequisite

Biomass boilers

A halfway house between a traditional boiler and a renewable heating system, these systems burn wood rather than fossil fuel.

They qualify as a source of renewable heat, despite the fact that they do actually burn carbon in the form biomass. The reason for this is that biomass boilers burn wood pellets, which are either made specifically from sustainably grown wood, or from offcuts produced in sawmills and other wooden manufacturing processes.

The idea is that sustainably grown wood captures carbon from the atmosphere as it grows and I carbon is emitted when it is burnt. The net effect is to not release any additional carbon into the atmosphere.

In the case of pellets made from offcuts, the theory is that burning them in biomass boilers in order to recover heat is preferable to simply throwing them away. Fair point.

Biomass boilers require more maintenance than heat pumps, particularly from the homeowner, who in the case of a manually fed biomass boiler will need to top up the boiler hopper regularly. The amount of effort involved is very similar to that of a wood-burning stove or open coal fire.

In my experience, there’s a fair amount of tinkering needs to be done with biomass boilers to keep them running smoothly. The grate upon which the pellets are burnt needs to be kept clean. Some boilers have an automatic maintenance process to keep this clear of ash, but they don’t always work perfectly so user intervention is often required.

Unless you have a automatically fed boiler, you will also need to hump a load of 10 kg bags of wood pellets into your boiler room every few weeks when the delivery arrives. If you are elderly or just don’t want to have to go to such effort on a regular basis, you’ll want to think carefully about whether biomass boilers are the right choice for you.

Biomass boiler advantages

Carbon neutral
Qualify for money under the renewable heat incentive (RHI)

Biomass boiler disadvantages

Require regular maintenance by the homeowner
Can require manual lifting of pallet bags from your driveway to boiler room
Occasionally get blocked, requiring the homeowner to roll their sleeves up and clear the grate

Solar thermal panels

Solar thermal panels absorb heat energy from the sun and then transfer this heat via a heat exchanger to a central heating system to heat the home, or a hot water cylinder to provide domestic hot water.

It stands to reason that the more sun you have shining on one of these thermal panels, the more efficient and effective it will be. The sun doesn’t always shine in Scotland, unless you live in Dundee that is! However, solar thermal panels still working compliments and when the sky is grey and overcast.

These systems also make use of an energy storage system which means the sun doesn’t need to shine all the time for them to work.

Solar thermal panels tend to be one of two types: either flat plate collectors or the more efficient vacuum tube collectors. Such systems will work best if your roof is south facing, but you can install on the ground if you wish, provided they are away from the shade of trees and other buildings.

Solar thermal is a form of renewable energy, which means you can apply for money via the renewable heat incentive (RHI), thereby bringing down the overall cost.

Solar thermal panel advantages

Require less space than solar PV panels
Simple technology with no moving parts requiring no maintenance
Renewable energy which qualifies for the renewable heat incentive

Solar thermal panel disadvantages

Less efficient during the winter when the sun is less bright
Longer payback period of initial investment

Solar PV

Solar PV panels are a great way to reduce your electricity bills, reduce your carbon footprint and even get paid for the surplus electricity you generate.

They work by harnessing energy from the sun, which is converted to electricity than be used in the home or exported to the grid if it is surplus to requirements.

If you have sufficient space on your roof and it is not shaded, solar PV is an excellent option.

Although the feed in tariff scheme was closed to new applicants in March 2019, a replacement scheme has been created to continue to incentivise the generation of renewable energy on a small scale. This new scheme is called the smart export guarantee (SEG) and is available throughout the UK. The SEG can make a huge difference to the economic viability of solar PV.

Solar PV is relatively cheap to install and requires very little maintenance.

When coupled with other renewable forms of alternative heating, such as an air source heat pump, the benefits of solar PV are multiplied.

Even without being used in combination with other renewable heating, solar PV can save you a significant amount of money. For example, according to the energy saving trust, for a four-bedroom detached property with a hot water cylinder and in the case of somebody who is home all day, savings could be as high as £360 per year.

Solar PV advantages

Renewable energy – does not contribute to climate change
Relatively cheap to install
Low maintenance
Can be used in conjunction with other renewable heating, such as heat pumps

Solar PV disadvantages

Not suitable for shaded areas
Requires significant space on your roof

Summary

There are many alternative heating systems on the market today. Traditional fossil fuel based heating systems are being phased out in favour of renewable systems that do not contribute to climate change.

If your gas or oil boiler is due to be renewed soon, it is worthwhile investigating alternative heating systems because they will reduce your carbon footprint and could also save you a significant amount of money.

Popular alternatives include air source heat pumps and ground source heat pumps, with the former being cheaper and less disruptive to install.

Biomass boilers tend to require more upkeep and maintenance than heat pumps, but remain a viable choice if you want to go green and take advantage of the renewable heat incentive.

Finally, if you really want to demonstrate your green credentials, consider combining solar PV with a heat pump heating system, which will multiply the benefits that either one alone would provide.

If you’ve read this far, you might be interested in our article on how to find a heat pump installer, which will tell you what to look out for and what your next steps should be if you are interested in getting a heat pump installed.

12 September 2020

Heat Pump Misconceptions

Having dealt with literally thousands of ground source heat pumps and air sour c e heat pumps, the heat pump community have heard all manner of myths surrounding heat pumps ranging from the sublime to the ridiculous.

We recognise how confusing it must be for people considering heat pumps to distinguish between fact and fiction so we’ve compiled a list of heat pump misconceptions to demonstrate what you might hear and what is actually correct.

“Heat Pumps do not work with radiators”

This is one of the most common heat pump misconceptions but certainly for correctly sized and installed heat pumps this is not the case. Heat pumps can work perfectly well with radiators and can also be integrated with underfloor heating systems too.

It’s possible to achieve flow temperatures of 65˚C via heat pumps but to ensure the lowest possible running cost, experts recommend where possible, to increase the surface area of the radiators by around 30%. This usually isn’t a problem as most radiator systems are naturally oversized anyway.

“Heat Pumps need a back up boiler as they can’t provide all my heating and hot water on their own”

This simply isn’t true and is another favourite on the list of heat pump misconceptions. Heat pumps will supply 100% of your hot water needs and 100% of your heating needs 100% of the time. What’s more, depending on whether you’re installing air source heat pumps or ground source heat pumps, the efficiency rate is between 300% and 400% respectively compared to just 75% to 85% for a fossil fuel boiler.

“I don’t have enough land area for the pipe work”

One of the most common heat pump misconceptions occurs in relation to the amount of space required for the groundworks for heat pumps. In the case of ground source heat pumps, a reasonable amount of land is required for the traditional ground loop or ‘Slinky’ system of pipes as it is also known. However, where the available land is very small, boreholes for heat pumps could be an option although this is admittedly more expensive.

The space requirements are much less restrictive for air source heat pumps although there are regulations surrounding placement of the units which your professional installer will discuss with you when compiling your quotation.

“Heat Pumps can’t get my domestic hot water to a high enough temperature”

Most people have a bath or shower with a water temperature between 39˚C and 44˚C. It’s possible to achieve a stored temperature of over 60˚C (although not all manufacturers can achieve this) which is certainly hot enough for all standard domestic needs and puts to bed just another example of the heat pump misconceptions you might encounter.

“Heat Pumps are only suitable for new build and not existing properties”

This statement can also be found on many a list of heat pump misconceptions. Like any heating system, heat pumps are more efficient in well insulated new build houses where they are often combined with underfloor heating systems to make full use of all the available space within the property. However, heat pumps are also a perfectly good option for existing housing stock. Over the years we have successfully retrofitted hundreds of ground source heat pumps and air source heat pumps helping owners save substantially on their fuel costs and in some cases to escape fuel poverty.

“Heat Pumps; they don’t really work do they?”

They absolutely do! The advantages of heat pumps are there for all to see for those prepared to invest the time and money to find out for themselves and not believe propaganda issued by greedy fossil fuel energy companies.

5 September 2020

Renewable Heat Incentive (RHI)

UPDATE April 2022: The Renewable Heat Incentive (RHI) has now ended. If you are in England or Wales and live in an eligible property, you might be able to take advantage of the Boiler Upgrade Scheme (BUS), but for those of us not living in those areas, we hope there will be a replacement scheme announced by Government at some point. We’ll provide an update on this website whenever an update is available.

The Home Energy Scotland Loan has been introduced, so you can apply for that now if you want.

Industry has been lobbying Government for a number of years to get more support for renewable energy products such as ground source heat pumps and air source heat pumps because of the value we believe these products offer consumers and the overall positive impact they can have on the environment.

We were therefore delighted that on April 9th 2014, government confirmed the launch of the domestic Renewable Heat Incentive which provided exactly the support for heat pumps and renewable energy we had fought so hard for.

If you have an RHI query, please request a callback using the form on this website.

If you’re not quite ready to make that call, read on for more information or watch this helpful video from the helpful folks at The Green Age.

What is the Renewable Heat Incentive (RHI)?

The Renewable Heat Incentive (RHI) is a financial support scheme for renewable heat. The scheme remains open for applications and is administered by the energy regulator Ofgem with the purpose of supporting and rewarding households who move away from fossil fuels for heating their homes.

Working in a similar way to the Feed-in-Tariff for solar photovoltaic (solar PV) systems, owners of heat pumps can be paid according to the total heat load of the property in kilowatt hours, for seven years tax-free.

It should be noted however that air to air heat pumps do not qualify for RHI payments.

What are the payment levels under the Renewable Heat Incentive (RHI)?

The amount of money you can receive under the Renewable Heat Incentive will be dependent on a number of factors including:

Renewable technology installed (ground source heat pumps, air source heat pumps, solar thermal)
Deemed heat load (the amount of heat likely to be generated by the renewable energy heating system)

The government assumes a 20 year lifetime for renewable heat technologies and has factored in the lifetime (i.e. 20 year) costs of operating the renewable heat system into the tariff values which are paid over 7 years. So, in effect, you are paid for 20 years of operation within a 7 year period.

An indication of the payments you could potentially receive can be viewed on our RHI Payments Table.

Participants will receive RHI payments quarterly in arrears for seven years. Tariffs will change annually in line with the Retail Price Index (RPI).

At the time of writing, the most recently updated tariffs published by Ofgem are for June 2020. Tariffs for air source heat pumps (10.85 p/kWh renewable heat) are significantly higher than the tariff available for biomass (6.97 p/kWh renewable heat. Tariffs for ground source heat pumps are much higher (21.16 p/kWh renewable heat), which is almost double the tariff for air source and is on a par with the solar thermal tariff.

The table below summarises these figures, which are also available on the Ofgem website where you can find out more about the scheme and how to apply.

	Air source heat pump	Biomass	Ground source heat pump	Solar thermal
Tariff (p/kWh renewable heat)(Applications submitted between 01 July 2020 and 30 September 2020 incl.)	10.85	6.97	21.16	21.36

Table 1: RHI tariffs as of June 2020

If you have previously received public funding for your heat pump system, such as the Renewable Heat Premium Payment, this must be declared as part of the application process. This will then be deducted from RHI payments under the scheme. Initially, a deduction equal to one twenty-eighth of the value of the prior public funding received will be made from each quarterly payment.

Who is eligible to receive the Renewable Heat Incentive (RHI)?

The domestic RHI scheme will give financial support for an eligible renewable heating system that heats a single domestic property in Great Britain. The property can be on or off the gas grid. Payments will go to the owner of the system.

To help with the costs of installing a heat pump, the following groups will be eligible to apply for the domestic RHI (and all receive the same tariff):

Owner occupiers
Private landlords
Registered social landlords
Self-builders
Third party owners of a heating system

Self-builders are defined as those who have built or commissioned a home for their own use, either by buildingthe home on their own or working with builders. Second homes are also eligible for the RHI. These are homes that are not a person’s main residence. Applicants for second homes will have to install metering equipment which will measure the amount of heat used.

New Build Properties – 183 Day Occupancy

The domestic RHI requires that if a property is occupied for less than 183 days, in a 12 month period, a heat meter must be installed to measure renewable heat use and determine payments, instead of payments being based on the annual heat demand specified on the property’s EPC.

This occupancy requirement ensures that the Domestic RHI delivers value for money for the taxpayer by not overpaying for renewable heat systems installed in properties that are not continuously occupied (for example, second homes).

This had resulted in the unintended consequence of eligible new self-builder properties having to wait 183 days prior to scheme application or installing heat meters as they are unable to provide evidence that they have lived in their homes for at least 183 days in the previous 12 months.

To overcome this, it was proposed that the regulations were amended to make eligible new build properties exempt from the 183 day occupancy requirement in the 12 months prior to application to the scheme. Thereafter, these participants would be subject to the standard ongoing obligations which included the annual declaration that the property had been occupied for 183 days or more in the last 12 months.

New build systems would not be eligible for the scheme. This meant properties in which the renewable heating system was installed before it was inhabited for the first time. This included applications from house builders and housing developers, as well as anyone who owned a new build property, including legacy applicants. The only exception was self-build homes (see above definition).

The renewable heat installation must be certified under the Microgeneration Certification Scheme (MCS). The installation will need to meet the MCS standards that applied at the time of installation, rather than the current standards.

All systems installed between 15th July 2009 and the launch of the RHI were eligible provided they met all the other criteria (referred to as “legacy applications”).

Other eligibility requirements of the Renewable Heat Incentive (RHI)

Before applying for RHI support, all applicants including legacy applicants needed to ensure that:

A Green Deal Assessment (GDA) had been carried out to find out which energy efficiency measures were cost-effective for the property;
Loft insulation (to 250mm) and cavity wall insulation had been installed where the measures were recommended by the GDA; and
Where the GDA shows the required loft and cavity wall insulation was yet to be installed, an updated Energy Performance Certificate (EPC) was obtained following installation, as proof of installation (or valid evidence provided proving why installation was not feasible)

The only exception was for self-builders who built their property to current building regulations who simply needed to submit an EPC.

All applicants must agree that they are willing to take part in a metering scheme if their property is chosen by DECC as a property to be metered. There will be an extra incentive for applicants who install metering and monitoring service packages of £230 per year for heat pumps.

Legacy applications and the Renewable Heat Incentive (RHI)

Installations of heat pumps since 15th July 2009 were eligible for the RHI, subject to meeting all of the other RHI criteria. To manage the potentially large volume of legacy applications and avoid a backlog administrators were working with Ofgem to develop an approach to phasing legacy applications over a period of time after the launch of the scheme: that is, staggering the dates when legacy applicants could first apply for the scheme. The last date for submitting a legacy application was Wednesday 8th April 2015.

To find out what this could mean for you and your home contact us using one of the forms on this website.

3 September 2020

Advantages of Heat Pumps

Despite a number of heat pump misconceptions there are many significant advantages of heat pumps ranging from reduced running costs and excellent efficiency gains to combining with Underfloor Heating systems. Below are just a few heat pump advantages for you to consider.

Using Heat Pumps to reduce running costs

One of the advantages of heat pumps is that because they move heat rather than creating it by burning oil or gas, they are much more efficient with average savings of over 60% for ground source heat pumps (almost as much as geothermal heat pumps) and 40% for air source heat pumps. As a result, a heating system using heat pumps will provide a realistic return on investment over a much shorter period of time.

Combating unstable oil prices

Oil prices are susceptible to large price hikes, particularly during the winter when you need your heating the most. Heat pumps totally remove this problem providing cost-effective, reliable heating whenever you need it. Heat pumps also remove the dependency on unreliable fuel deliveries which can be further delayed during adverse weather conditions – just two more examples of the advantages of heat pumps.

Increased efficiency

The efficiency of heat pumps is beyond question. For every 4kW of heat moved into your house via ground source heat pumps, only 1kW of electricity is consumed. This gives a perceived efficiency of 400%, sometimes stated as a Co-efficient Of Performance (COP) of 4:1. In the case of air source heat pumps, you can expect a COP of 3:1 which while slightly lower, is a still a huge improvement on boilers which have only around 75% to 80% efficiency rates over their lifespan truly demonstrating the advantages of heat pumps*.

*It’s worth remembering that to get the most efficiency from your heat pump, it pays to make your home as well insulated as possible. Less well insulated homes may not achieve the highest COP levels. COP levels will also depend on the emitter system (radiators, etc) installed.

Grant schemes for Heat Pumps

There are a number of renewable energy grants which you may be able to benefit from when installing heat pumps including the Renewable Heat Incentive (RHI).

The Renewable Heat Incentive (RHI)

The Renewable Heat Incentive (RHI) which launched in April 2014 aims to provide further air source heat pump advantages and ground source heat pump advantages by making payments to owners of these systems for the energy they produce, much like the Feed-in-Tariff for Solar Photovoltaic (Solar PV) systems. Payments are tax-free, index-linked and last for a period of seven years.

No scheduled maintenance

Heat pumps are extremely reliable with minimal regular maintenance required. Our heat pumps have a planned life span of 25 years with no loss of efficiency which again demonstrates one of the many advantages of heat pumps especially when compared to boilers which can lose up to 2% efficiency for each year of operation and have a usable life span of only around 12 years.

Warranty

Another of the advantages of heat pumps is that because they are a well-established technology, many manufacturers offer a 5 year parts and labour warranty on ground source heat pumps which is separately bonded by independent insurance giving you even more peace of mind.

For additional peace of mind, flexible warranty and service options are available beyond the length of the standard warranty period.

Lower environmental impact

Coupling your heat pump to a green electricity supply such as solar photovoltaic (solar PV) can provide your heating, hot water and electricity demands with zero Carbon Dioxide emissions.

Another factor worth mentioning here is the benefits to local air quality. Particularly switching from, say, coal will significantly improve local air quality. If you’ve ever walked down the street on a winter’s morning in an area where most people use open coal fires to heat their homes, you’ll have noticed the acrid smoke that lingers in the air. Not quite as bad as the “pea souper” smogs that used to be commonplace in our major towns and cities in the olden days but still unpleasant.

Some people have drawn attention to the noise that air source heat pumps can make. However, the noise is no louder than a standard combi boiler and its impact can be mitigated through correct siting of the unit and appropriate sound proofing.

The safety advantages of Heat Pumps

People often don’t consider the dangers that conventional heating systems could pose, particularly as the systems age. Heat pumps can eradicate these issues as they don’t use volatile or combustible substances.

Low risk of accidents

Almost 150 people a year are killed by home explosions and carbon monoxide poisoning linked to faulty boilers. Heat pumps are completely free from any contaminants which may cause harm to the environment and they do not emit any noxious gasses which could harm you or your family.

Hot water safety

On average nearly 600 people a year suffer serious scalds from hot water and radiators. Most people don’t realise:

Hot water at 70˚C takes less than half a second to burn
Scald burns are the third most common reason for admission to hospital for under 5’s
7 children a week require hospital treatment involving painful skin grafting and permanent scarring

Easy installation

Any competent plumber can install your heat pump and in case you have any queries, there are many good maintenance and installation companies out there.

So, if you’re interested in finding out more and possibly installing your own heat pump, please get in touch for a quote.

4 August 2019

50% Cost Saving with a Ground Source Heat Pump

John and Hazel Hunter installed two ground source heat pumps in autumn 2009. They own a Tower House in Central Scotland, which presented some challenges to the project, partly because of its location but also because of the fact that it is an A listed building. An A listed building is roughly equivalent to a Grade 1 listed building in England, so you can imagine that integrating modern heat pump technology into the historic building in a sympathetic way that kept them on the right side of the authorities was a tall order.

The project was a great success and exceeded their expectations in terms of practicality and cost.

Project Details

The property is a detached tower house in central Scotland and the pre-existing heating system ran on LPG. Several options were considered for the new heating system, some of which were ruled out very early on after initial feasibility assessment. The replacement heating system would be powered by two IVT HT Plus E11 ground source heat pumps and the heat would be distrubuted via radiators.

The project began in September 2009 and was completed by November 2009, a period of three months.

The couple applied for Renewable Heat Incentive (RHI) benefit and the payment levels vastly exceeded their expectations.

Why Heat Pumps?

John and Hazel decided to look at alternative ways to heat their property because the price of LPG was on the rise. An air source heat pump could have done the job but, one evening, sitting in front of the television, they saw a property very similar to their own on the Channel 4 programme Grand Designs. Kevin McCloud was waxing lyrical about the merits of the project, but by far the most interesting aspect to the Hunters was the heating system, which comprised ground source heat pumps.

The Installation Process

The installation process took quite a long time – almost three months, partly due to problems with the ground works.

The installation required more than 1,400m of 40mm pipes, 100m of which had to be lagged with insulation material and be buried a metre deep below the surface.

The house sits immediately on top of a rocky outcrop so getting to a depth of a metre required digging through the underlying bedrock at points. Although there was no convenient body of water to allow installation of a water source heat pump, fortunately, the rock below the property was shale bearing sedimentary rock, which was easily removed with a mechanical digger.

Once the pipes had been laid below ground, the LPG boiler was removed and the new heat pump system was retrofitted to the old pipes and radiators.

The Result

Living with the new heat pump

The couple are very satisfied with their new heating system. Despite a few teething problems caused by dirt getting into the system, which were quickly resolved, things are now running smoothly.

There have been three breakdowns but due to the fact that they have two separate pumps controlled by a step controller, they have never been left without heating. This is a concept called redundancy, which means there is always a backup available.

Renewable Heat Incentive

The Hunters applied for the RHI payments, a process that they found very straightforward, except for the unforgiving nature of the Ofgem website and the somewhat bureaucratic nature of the process, particularly the rigid interpretation of the SPS calculation.

However, it was all worthwhile because the level of payment they will receive has exceeded their expectations hugely.

Impact on Heating Costs

The heating bill for the couple halved overnight. The cost of the excavations was considerable due to the need to dig through bedrock, coming in at around £35,000, however, the payback period of this initial investment is just 10 years, even without taking the RHI payments into account.

Benefits of Ground Source Heat Pumps

The cost benefits speak for themselves – who wouldn’t enjoy having their heating bills halved at a stroke? Yet that’s exactly what the Hunters have had happen to them.

The house is warm all the time the heating is running, which is the case for around 9 months of the year. The system also has an auto-adjustment feature to account for times when the outside temperature is particularly cold.

Due to the colder climate in Scotland compared to other parts of the UK, a water source heat pump can sometimes be a good choice, as has been proposed near the River Tay, but the ground source system installed by the Hunters is doing fantastically well and there seems no reason to change.

4 August 2019

Boreholes for Heat Pumps

When embarking upon a project to install a ground source heat pump, one has a decision to make about the orientation of the ground loop. There are a couple of different options available for the installation of the pipework or “ground loop” which collects the stored solar heat used by heat pumps. The first option would be a shallower, slinky or straight ground loop where the pipes are laid in trenches beneath the ground, or if space is at a premium, there is the more expensive option of using boreholes, which can be drilled straight down into the ground. Of course, if we had more volcanic activity in Scotland, we could take advantage of geothermal heat but that’s sadly not an option in this part of the world.

Specification and location

Boreholes for heat pumps will have been designed and specified to provide sufficient energy collection from the ground to allow the system to operate efficiently. Careful planning is required to ensure that the borehole is installed according to the manufacturers design and it is recommended only to deal with drilling companies who are affiliated to the British Drilling Association providing you with greater confidence that the drilling process is being conducted by true professionals.

The depth of the borehole will be dependent on several variables including the heat load of the property and the geology of the local ground, both of which should have been established by a qualified professional during the project specification and site survey. The location of boreholes for heat pumps is always site specific and must be determined during an in-depth planning process.

Drilling

There are several types of drilling rig available, which are better suited to different ground conditions and can be of varying sizes to accommodate the drilling of boreholes from the smallest gardens right up to the biggest building sites. A common technique is a rotary drill, where the rig rotates drilling rods into the ground, cutting their way as they go. This method is relatively clean, although there will be some spoil and a little water discharged, though this should be cleaned up by the drillers before they leave site. Using this method of drilling can be fairly quick, with progress of between 50 and 60 metres per day, depending on the underlying geology.

How many holes, how deep and how big?

The specification of the boreholes for heat pumps is usually calculated using software that takes into consideration the size of the heat pump, the geology of the ground and the heat losses of the house or building. Boreholes will usually be between 60 and 120 metres deep and may consist of any array of anything between 1 and 12 boreholes depending on the project size. A standard borehole is approximately 120 – 150mm in diameter.

What goes in the borehole?

Once the drilling of boreholes is completed, the borehole loop is inserted into the hole. This loop consists of a pair of plastic pipes that are joined together at the bottom by a ‘U’ bend. This bend is joined by a method called electro-fusion welding and is manufactured and tested in the factory. Once the loop has been lowered into the hole it must be filled with water and pressure tested.

Backfilling the boreholes

As soon as the borehole loop has passed the pressure test, the hole is backfilled. It is important that the backfill material is the correct type and that it fills the hole completely. This is achieved using a natural clay compound called bentonite, which is mixed with water into the bottom of the hole and then solidifies over time. When finished, all that remains will be the tails of the pipe protruding approximately 500mm from the ground. The drillers will attach end taps to these pipes to protect them. This then leaves the boreholes for heat pumps ready for connection to the manifold by others.

A professional company should provide a fully project managed service to meet all your project requirements ensuring the work is professionally undertaken and completed to an exacting standard.

You can use our online directory to find an installer for your own heat pump project.

24 April 2019

How Much Space Is Required for a Ground Source Heat Pump?

Top Takeaways

A horizontal ground loop is usually buried about 2 metres underground.
On average, the ground loop is approximately 200 metres long.
The space requirement for installing the ground loop is about 700-800 square metres.
A slinky arrangement can save space, as can drilling vertical boreholes instead of horizontal trenches.
Vertical boreholes for a ground source heat pump will need to be around 60m deep and will cost more than horizontal trenches.

With the rise in popularity of renewable energy, ground source heat pumps have turned into a very intriguing option for a lot of homeowners. People all over the United Kingdom are interested in the ability to stay warm in the winter months and cool during the summer, without the need for a boiler or air conditioning.

A ground source heat pump is a solution for homes that transfers heat between home and the ground. By moving heat from one space to another, the temperature inside the home can stay optimal. This comes in particularly handy during the coldest months.

But how much space does such a system take up?

Getting a ground source heat pump sounds like a great idea, but what exactly goes into the process and how much space do you need to take advantage of it? Here’s a closer look at the space requirements, plus some common questions and answers in regard to this heating and cooling technology.

Having A Ground Source Heat Pump Installed

Once a person decides on going forward with a GSHP, the design and installation process begins. Companies will often suggest taking the energy from the water going through the pipes in the ground, partly because this offers a stable source of heat, as opposed to an air source heat pump, which is subject to the vagaries of the UK weather.

These pipes are usually about two meters deep, but an alternative is to use vertical boreholes if space is of a premium. This is similar logic to the idea that in crowded cities, where space is at a premium, the only way to build more accommodation is to build up – hence the high-rise blocks of flats in many UK city centres. However, in the world of the ground source heat pump, the only way is down…

Groundwater tends to remain at a fairly constant temperature of approximately 11°C all year round in the UK, which gives enough heat for a heat pump to extract and deliver to your home.

One of the most important parts of the design process is to match the ground loop to the heating load of the home. Inappropriate design can result in poorly-sized systems that fail to do their job properly. This can result in a system that is expensive to run or, in the worst case, one that fails to provide sufficient heat energy to keep the property warm.

After Installation

While the installation process can seem complicated, the result is a very efficient, easy-to-use system for controlling the temperature of your home. The installation process should always be done by professionals, although some people will try to tackle things by themselves. Beware of this temptation! Without the proper knowledge, you can find yourself landed with an expensive and ineffective system. If in doubt, get the professionals in.

Once up and running, the system can be operated without a lot of baby-sitting from the homeowner, so there is not really much to do after installation. There are basic maintenance checks that should be done from time to time, and routine servicing is a very good idea, but mostly installations work as they should for years.

Common Questions and Answers

Since ground-sourced heating and cooling, and sustainable energy as a whole, is still relatively new, many home owners around the UK have questions before they take the plunge. Below are some of the most common questions, with answers provided.

Do you need planning permission for a ground source heat pump?

Most home owners will not need permission, but it is always encouraged for people to look into their own unique situation individually. The majority of homes will be allowed it as permitted development.

Those living in a listed building, or a conservation area, need to look into applying for a permit before installation. Every area is going to have slightly different rules and regulations though, so there is no blanket yes or no answer.

What’s a typical ground source heat pump pipe length?

Ground loops range in size but are typically going to be about 200 meters long. Since many homes will need two or three, with separation between each of them, it is recommended to have about 700-800 square meters to operate with.

This can be a lot of space for a homeowner to have to find, but there are some alternatives. A slinky-like setup needs less space because this allows for installation of a length of pipe in a smaller area but can be less efficient because of the loops transmitting heat between each other underground. Vertical boreholes are another option, but they can be costly due to the drilling process requiring specialist equipment and being more energy and time intensive.

Inside the home, there will be no difference. The entire setup will take up about the same amount of size as a traditional heating and cooling unit.

How deep is a ground source heat pump?

For horizontal loops, the ground is only dug up a few meters. For a vertical loop, most will need to dig at minimum 60 meters.

What are some ground source heat pump advantages?

Operational costs for a ground source heat pump will be pretty low, which is a major advantage for home owners once things are set up and used consistently. The cost stays low thanks to only the compressor needing electric energy. The heat pump is more efficient than a pure electrical heater would be and this is one of its great strengths.

Another advantage is that a GSHP can work for cooling and heating needs. With other setups, a separate air conditioner and boiler are needed. For a GSHP to work for both, the valve just needs to be reversed to change the circulation of the fluid.

Finally, the value of a property can go up with a properly installed ground source heat pump. Since installation is the biggest cost, having one already set up in a home will be beneficial when selling.

And don’t forget government grants and financial incentives, such as the RHI, which can tip the balance in favour of a heat pump system, especially over the lifetime of its operation.

What are the disadvantages of ground source heat pumps?

As mentioned earlier, perhaps the most significant disadvantage is the installation cost. It costs considerably more than putting in a standard conventional boiler or air conditioner. This initial investment is tough for some people to handle, but in the long run, things often more than even out, especially if you qualify for the financial incentives mentioned above.

It can be challenging to find groundwater for a deeper system in specific locations as well, such as in areas of Scotland underlain by hard rock such as the Highlands. That can be a problem for some homeowners in those parts of the country. It is important to research each specific situation first before fully committing. There are alternatives you could consider if you don’t have the option to drill a borehole, such as an air source heat pump.

Any DIY ground source heat pump tips?

For the vast majority of people…don’t try. The installation process is somewhat complex, and if done correctly, it can last a long time. Unless a person has experience with geothermal systems, it’s better to leave it up to professionals.

Those who know enough to try installing a system themselves will not pick up anything useful from this basic overview. They will already know more than enough to tackle a project of this size.

Final Thoughts

There is little doubt that a ground source heat pump can provide a lot of benefits for a home. Not only can it save on monthly bills, but by using renewable energy, it is much better for the environment. It can be a pretty big commitment to get it up and going initially, but the pay-off in the long run can be excellent.

16 March 2019

Video – How Heat Pump Heating Systems Work

The video below is an excellent walk-through of how a refrigeration cycle works.

The video features a system that uses sight glass instead of copper piping, allowing the narrator to show the inner workings of a heat pump system. You will see the refrigerant itself as it evaporates in the pipes, slowly changing from liquid to gas, absorbing heat as it does so.

The narrator is very knowledgeable and I’m sure you’ll learn a thing or two, even if you’ve been working on HVAC systems for a while.

19 January 2017

Air source Heat Pump Noise Levels

Do Heat Pumps Make Noise?

A very common question these days, and one that is fortunately very easy to answer. Before diving into the detail and comparing heat pump noise levels, banging on about decibels and noise abatement, let’s just remind ourselves of a simple fact…

Pretty much all household appliances make some sort of noise!

There, I said it. And it’s true.

When was the last time you used a silent kettle, or a quiet vacuum cleaner? Even a traditional combination boiler will belt out over 40 decibels, so it could be argued that when we ask about air source heat pump noise, we’re asking the wrong question.

Even your beloved spouse/significant other lying next to you sleeping will make some noise. Simply breathing produces around 10 decibels, which we are normally quite happy to put up with – and if that bothers you then I would say that heat pump noise is the least of your problems!

OK, now I’ve got that little reality check out of the way, let’s answer the question directly…

The Short Answer Is…

Wait for it…

Yes and no!

Sorry about that, I hate it when I ask a question and someone tells me that “It depends”, but that is the reality. It’s a reality with so many things in life, but it is especially true with heat pumps.

You see, you’ll always hear the story about the person who had a heat pump installed outside their bedroom window and how it kept them awake all night, causing them to sleep in late, which made them ultimately lose their job. Then their wife left them, and they finally ended up on the street, penniless and colder than ever.

But there will always be extreme examples if you look hard enough. The reality is that a typical heat pump is no louder than a standard combi boiler. The problems that can arise are usually related to poor siting or poor installation of the heat pump. That is why it is so important to find a good, reputable and professional installer to make sure you get system that runs quietly and causes no disruption to anybody’s sleeping pattern.

Heat Pump Noise Can Be Mitigated

Sir Thomas Beecham once remarked that, “Brass bands are all very well in their place – outdoors and several miles away”! Whilst such distance is not required for a heat pump installation, you would be wise to consider the location of your installation carefully. Air source heat pump noise right outside your bedroom window might be a problem. Twenty air source heat pumps’ noise located the other side of a thick, soundproof wall might not.

If you find yourself already stuck with a noisy heat pump, there are way that you can reduce or eliminate the nuisance.

For example, you could build an enclosure around the unit and clad it with noise-reducing acoustic panels, which can be obtained relatively cheaply.

Another option would be to get an HVAC engineer to come out and take a look at your heat pump to see whether there is a fault that could be giving rise to excessive noise levels. Sometimes a straightforward service can help – it will certainly help your unit stay efficient and help to prevent costly repairs later on.

How About Avoiding Heat Pump Noise In the First Place?

This is certainly possible. The different brands of heat pump have different noise characteristics, with some being much quieter than others.

One of the best manufacturers in terms of keeping their products quiet is Mitsubishi Electric and their Ecodan range of air source heat pumps. This brand takes noise mitigation very seriously and has even won awards for their quiet heat pumps.

If you go for their 8.5kW unit, you get the added bonus of supporting Scotland’s economy because it’s made down the road in Livingston, West Lothian.

In Summary

Any sort of household appliance will make some amount of noise, but an air source heat pump is no louder than a “normal” appliance of a similar sort, such as an oil-fired combi boiler.
Think about the location of your heat pump carefully. Where it is located can have profound implications for any noise nuisance it might cause.
Get your heat pump professionally fitted by a reputable company to avoid any issues caused by faulty or badly installed units.
If you find you are stuck with an existing noisy heat pump, there are ways that you can mitigate the problem so don’t despair.

I hope you found what you were looking for in this article. Please consider browsing through the rest of the site for more useful information. And feel free to get in touch via our contact form.

20 December 2016

Ground Source Heat Pump Problems

Things to Look Out For and What To Do If The Worst Happens

Ground source heat pump problems can be avoided if you have your system sized and installed by a reputable company that knows what it is doing. However, you might find yourself stuck with a poorly performing or malfunctioning system for any number of reasons. For example, you may have inherited the system from the previous owner, or perhaps you tried to cut corners yourself on the installation and are now regretting it.

Whatever the cause of the problems you are facing, rest assured that there is almost always a solution. This guide will help you troubleshoot the problems yourself initially and, if professional advice is required, tell you the right kinds of questions to ask of the technician who comes to investigate.

The Heat Pump System

Before we get into talking about the problems that can crop up, its worth spending a little time refreshing our minds about how a ground source heat pump works and the component parts that make up the whole.

A typical ground source heat pump system comprises the following parts.

The Ground Loop (the bit where the heat is sourced)
The “Heat Pump” itself – the mechanical heat engine part that serves as a fridge in reverse
The Heat Sink – e.g. your underfloor heating coils

These are the main bits of the system that you would need to look at to fix any problems and it is useful to bear these pieces in mind as you read on.

If you are keen to go into more detail, you can find more in depth articles elsewhere on this site.

Do you need a professional?

Depending on your level of knowledge and technical competence, you might need to consult a professional at some stage. However there are some basic checks that even a complete lay person can easily carry out. Let’s start with those.

Customer-Led Troubleshooting

Before you reach for the phone, its a good idea to investigate the problem, if for no other reason than you will be better able to describe what has gone wrong to the technician so that he or she can be prepared when they visit you.

Is the system plugged in and receiving power? Obvious I know but this can be overlooked quite easily. The potential embarrassment (and cost) when the engineer comes out, plugs the unit back in and then goes on his merry way having charged you a nice callout fee is worth avoiding.
Visual check. You might be surprised as how much you can find out just by looking in the right places. If something looks wrong, the chances are that it is wrong! So, check for leaks, worn or broken cables and other signs that something is amiss with your system.
Has your circuit breaker tripped? This is a very obvious thing to check and could save you having to go any further with your investigations. Just flick the switch on the breaker back into the “on” position and you’re back in business.
Have you set your system thermostat correctly? It is possible that you, a small child or a pet has accidentally knocked the thermostat and caused it to set the operating temperature to something that you don’t want. I’ve also seen heat pumps put into reverse by mistake (cooling instead of heating), so this is also worth checking.
Is water flowing through the heat exchanger? You can tell this by listening carefully or by touch.
Does your air filter or the coils require a change? If they have become dirty, this can impede the flow and cause your system to malfunction. Give them a clean or change them for new ones.
Is the pressure high enough in the loop system where the heat is absorbed or emitted?
Are the pumps operating correctly? A failed loop pump will cause the entire system to fail.

Professional Advice

If you’ve checked all of the above issues, then it’s time to get a professional on site. Make sure you find a trusted service engineer (personal recommendations are often the best way to ensure that the quality of the technician’s work will be of a high standard).

Some of the issues that might require professional intervention include the following.

Refrigerant problems. The refrigerant is the fluid that does all of the hard work inside your heat pump, so if there’s something wrong with that, it is likely to affect your system as a whole. Typical problems could include low refrigerant levels, scale or fouling of the heat exchanger or a problem with the reversing valve.
Warm air not warm enough. A common cause of this problem is that the flowrate of the air through the system is too high. This means that the residence time of the air is too short and it doesn’t get heated up enough. This problem is normally easily fixed by reducing the speed of the fan.
Generally reduced performance. Less than expected heating or cooling performance is often caused by reduced airflow and can be fixed by replacing the air filter.
High humidity inside the building. This is sometimes caused by an excessively high air flowrate or by the heat pump unit being too big for the job. Adjusting the speed of the fan can often resolve this issue.

If you do find yourself having problems with your ground source heat pump system, don’t panic. A careful visual check can sometimes resolve the problem.

And if you keep your heat pump regularly serviced, it should last you a long time.

If problems persist, obtain the help of a professional. Don’t forget that most companies will guarantee their work for a period of time. Make sure you use a reputable company, preferably based on personal recommendations and you will be fine.

17 December 2016

Heat Pump Services

As with anything mechanical, from time to time there is a chance that your heat pump might require attention from a qualified technician. If there are any problems, you want them fixed as soon as possible, without any fuss and without being hit with a large bill.

That’s where a service plan comes in.

Heat Pump Servicing

Heat pump technology is continuously improving and their reliability is getting better every day. However, if you value your peace of mind, it is important that you take steps to prevent your heat pump developing problems and that you have a safety net should your heat pump break down.

First, let’s have a look at the problem.

Heat Pump Repair Cost

So you’ve been using your heat pump happily and without any problem for a few years, but then just before your in-laws come to visit in the depths of winter, your heat pump fails. You’re stuck with snow on the ground, ice on the inside of your windows and you can see your breath in the bathroom. Not a recipe for a happy home!

If you are lucky enough to know yourself how a heat pump works, or you can get hold of a qualified engineer, you might be able to get the system up and running quickly, but the work could be expensive and there is no guarantee that a suitably qualified technician is available at short notice.

How much does it cost for a repair to be carried out on your heat pump?

The answer is, as it is so often, well it depends! But that’s not very helpful so I’ll try to elaborate.

Taking the Nibe brand as an example, you could expect to pay £140 for a sensor change evaporator, which might not seem too bad. On the other hand, replacement of the compressor (complete fridge unit) on a ground source heat pump would likely set you back around £4,000. Ouch!

So, what can be done to guard against such unexpected bills?

Well, the first thing you could do is make sure that you look after your heat pump system properly, which means servicing it regularly. All good service engineers will have a detailed heat pump service checklist that they will go through during each service to ensure that nothing is missed.

Regular servicing is especially important as your manufacturer’s parts and labour warranty draws to an end. That’s when you should give serious thought to taking out a maintenance contract or service plan.

Heat Pump Service Cost

A decent plan could set you back as little as £18 per month, which is less than a lot of phone contracts and likely to be a good option for many. This type of plan would typically cover breakdown and would ensure you could get a fully qualified, competent heat pump engineer to come out at short notice to fix your heat pump before your in-laws arrive on that cold winter’s evening.

In addition to breakdown cover, it’s a good idea to take advantage of the annual service that many of these plans offer. That way any worn or damaged parts can be spotted early and replaced or fixed before they become an issue.

In Summary

So, a ground-source or air source heat pump maintenance contract is a worthwhile investment that will ensure your system continues to operate correctly for many years to come. It can also make sure that any ground or air source heat pump problems you might have in the future are swiftly and professionally dealt with and that any interruption to normal service is kept to an absolute minimum in the event of a breakdown.

Nobody likes having a cold house, especially not when the in-laws are visiting, so sign up for a maintenance contract for your heat pump today!

3 October 2016

GSHP District Heating – Economies of Scale with Ground Source Heat Pump Systems

GSHP District Heating Pipework being replaced

Ground source heat pumps are well suited to district heating applications and there are many good examples of their use in countries across the world.

Before we get into the pros and cons of these systems, I think a quick explanation of what they are is in order.

What is a district heating system?

District heating systems are simply systems that are powered by a central heat source instead of by multiple individual heat sources for each house, office or other building.

The system relies on well-insulated pipework to convey the heat generated by the central boiler/heat pump to all the buildings on the network.

There is usually a heating main that transports hot water from the heat source to the other buildings on the network. At each of the buildings served by the system, the heat from the heating main is transferred to that building’s heating system via a heat exchanger.

Having given up its heat to the building via the heat exchanger, the (now cooler) water in the heating main is pumped back to the boiler and the heating cycle is repeated.

Benefits of a District Heating System

Most of the benefits of a district heating system stem from the principle of economies of scale. Some of the main benefits are as follows.

Cheaper cost of installation. It is typically cheaper to install a single larger boiler than to install multiple smaller units. There is less pipework and fewer things to go wrong.
Cheaper to service and maintain. Servicing costs can be kept lower due to the fact that a service engineer only has one location to visit and a single unit to work on.
Fuel costs can be less. Operating a larger boiler means that it is possible to buy fuel in bulk. In the case of ground source heat pumps, the costs of pumping from a single borehole or trench are lower than from multiple ones.
Lower climate impact. For many of the same reasons fuel and servicing costs are cheaper, you can reduce your carbon footprint. There will be fewer miles travelled when service engineers only visit a single site, for example.

Where Can a District Heating System be Installed?

The answer to this is pretty much anywhere there are groups of houses, offices or other buildings that require heating. Provided the heat source(s) can be installed nearby and the individual buildings requiring heating are close enough together, a district system is possible.

If ground conditions are favourable, then a ground source heat pump district heating system can be a very attractive option.

How Does a Heat Pump Work?

how does a heat pump work diagram

When I first heard about heat pumps I’ll admit that I was a little puzzled about how they worked. I could get my head around geothermal energy because hot water coming out of the ground that had been heated by volcanic activity was no different to a traditional furnace heating up water to be used in a central heating system. All that’s really happening there is the substitution of heat from the earth’s molten core for the heat generated by a hot water boiler, the rest of the process is the same.

However, a heat pump does not generate heat – it moves heat from one location to another. Heating a building using cool (or even cold) water might seem too good to be true, but it is possible and is actually very common.

Heat pumps have been widely used for many years and, in fact, we all have one in our kitchen (our fridge). Heat pumps can also be used for more challenging jobs like heating a swimming pool (either with a GSHP or ASHP).

The science of heat pumps is well-established and can be explained using the laws of thermodynamics. At the most basic level, a heat pump moves heat from a heat source to a heat sink. What this typically means in practice is that the heat available in the ambient air outside, water in a nearby pond or river, or under the ground itself, is collected and then moved to a place where it can be used such as radiators or underfloor heating.

So how does a heat pump achieve this amazing feat?

Well, it all boils down to basic physics.

First of all, it is important to understand what heat is. Heat is a form of energy, which can be conceptualised as the amount of vibration that individual molecules or atoms exhibit. Remove all heat from a substance such as water and those molecules cease moving altogether. This is what happens at absolute zero, but absolute zero (0 degrees Kelvin or -273 deg C) is almost impossible to achieve. So even ice on a frozen lake in the north of Scotland has some heat in it.

If it is understood that heat is present even in cold river water, then the principle that this heat can be extracted and moved somewhere else starts to seem possible.

Under normal conditions, heat moves “downhill”, that is to say it moves from a hot location to a cooler location. That’s why your house cools down when it’s cold outside – some of the heat energy within the building moves downgradient to the cooler environment outside. What a heat pump does is use a small amount of (usually electrical) energy to reverse this natural process.

Picture of the inside of a fridge

The easiest illustration of a heat pump at work is in your fridge. You may have noticed that the back of your fridge is normally warm to the touch. The reason for this is that the heat present within the fridge compartment is removed by the fridge, using electrical energy, and then dissipated via the coils on the back of the fridge. Simples!

The process works by taking advantage of the properties of the refrigerant which is circulated around the heat pump’s components. The refrigerant absorbs heat from outside the building in the evaporator, where it changes state from liquid to gas. It then flows through a compressor, which circulates the high-pressure and high temperature refrigerant through a type of heat exchanger known as a condenser. In the condenser, the refrigerant changes from a vapour to a high-pressure liquid and gives off heat, which results in it cooling to a moderately warm temperature. At this point, the refrigerant is passed across an expansion valve, which reduces the pressure it is under. The low-pressure liquid then passes along the evaporator where it is provided with heat from outside causing it to boil and change state into a vapour, repeating the cycle over and over again.

The net result is that heat is absorbed from outside by the low-pressure liquid refrigerant in the evaporator coils as it boils, and the heat absorbed is then transferred to the inside of the building by the high-pressure refrigerant vapour in the condenser as it condenses to a warm liquid.

If you are interested in a more detailed explanation of how heat pumps work, please read my detailed article that covers the main scientific concepts involved, or check out the video showing the inner workings of a heat pump system.

Heat pumps come in a variety of different flavours. The main types being air-source, water-source and ground-source. Although they each get their heat from different sources (the clue is in the name folks!) they actually operate is very similar ways, thanks to those laws of physics that I mentioned earlier.

17 August 2016

Swimming Pool Heat Pump – Can a heat pump really heat an entire swimming pool?

When people first look into getting a swimming pool heat pump they are often somewhat incredulous. After all, not everyone is familiar with the technology and what it can do, which tends to give rise to some serious misconceptions that many of us have before we look into the subject in detail.

”How can a tiny heat pump get my swimming pool up to temperature?” they ask.

It’s completely understandable because the volume of water that needs to be heated is far bigger than the typical house’s domestic hot water tank. It does seem rather a big ask, particularly when there is a lot of information out there saying that heat pumps are less efficient when it comes to heating hot water for use in the home.

However, there are some important considerations that work in favour of the heat pump option.

Firstly, your swimming pool doesn’t need to be heated to as high a temperature as your domestic hot water. You won’t be washing dishes in it, or dipping a bucket into it for disinfecting your kitchen floor, so the temperature can be a lot lower. Besides, it is far more comfortable to have your pool at a typical “swimming temperature” rather than the temperature of a hot bath. If you’ve ever been for a swim in a pool that’s too hot you’ll know just how uncomfortable that can get!

This lower temperature allows the heat pump to operate much more efficiently and makes the use of heat pumps for swimming pools a viable option. This is a similar to underfloor heating, which people tend to be more familiar with, whereby the much larger floor area (compared with a traditional radiator) allows the house to be heated to a comfortable temperature despite the water in the underfloor heating system being cooler than in a traditional radiator.

So How Does a Heat Pump Work For a Swimming Pool?

The short answer is, “The same as for any other application”. Heat pumps work by moving heat from a warmer location to a cooler location. In the case of a ground source heat pump for a swimming pool, this would be moving heat from the ground loop buried in the garden adjacent to the pool and transferring it to the water in the pool.

It is possible for heat pumps to generate up to 7 times more heat energy than they consume during their normal operation. This is at the very top end of the range and relies on a large temperature difference between the warm side and the cold side, but it shows what can be achieved.

For more information about how heat pumps work, check out our introduction to heat pumps, which gives a more detailed explanation.

Will the chlorine in my pool (or salt) cause harm to my heat pump?

Many heat pumps are designed to work under such conditions, sometimes using titanium, or other metals that are highly resistant to corrosion, in the heat exchangers. Provided you choose a good quality pump that is designed for your particular application, you shouldn’t need to worry about damaging it.

For indoor pools, Is it better to put the heat pump inside where it can reduce the humidity of the pool room and warm the pool water as well?

One possible configuration of this kind of system could be to have the heat pump blowing its exhaust air out through a vent in the wall of the building. The air intake should be at the opposite side of the building and could be a simple vent.

While this is possible, and on the face of it might seem more efficient, it would actually result in a problem. Although the heat pump would be using warmer air, which has obvious efficiency benefits, after a time, the air in the building would end up being the same temperature as the air outside, which could be very cold during the winter months.

In most cases, it would be better to locate the heat pump outside and dehumidify using separate dehumidifiers installed inside the pool room. You would then be able to control the temperature of the pool water and the air in the building independently, which is obviously much better.

Always use a solar cover over your pool when heating your pool using a heat pump

In the same way that good home insulation is important for heating your house with a heat pump, you should always use a solar cover on a pool that is heated in this way. Not only does it have the capability to warm your pool up by as much as 8 degrees Celsius, but it also cuts down on evaporation, heat loss and chemical consumption, as well as preventing leaves from getting into your pool.

With a solar cover, you will be able to heat your pool more cheaply and reduce the impact you are having on the environment due to energy consumption and chemical usage. Covering the pool at night is especially important because the colder night air will cool down your pool more quickly.

Heat Pump Installation

Installing an air-source heat pump is pretty straightforward. It needs a level, hard standing base which can be as simple as a concrete slab, an electricity supply and any associated pipework. These days plumbing it in will be straightforward with “push-fit” pipes and connectors but you should always obtain the services of a qualified electrician to connect up the power supply, particularly as this will often need to be a 3-phase supply which is higher voltage.

What size heat pump do I need to heat my swimming pool?

The size of unit you require will depend on several factors, including whether you pool is inside or outside, in a windy or sheltered spot, whether you’ll be using your pool during the winter or summer, whether it has a cover and, of course, how big it is.

It is generally better to oversize the heat pump because this means the pump will heat up your pool more quickly, which is an important consideration when heating up initially for that first dip in the spring after the long winter chill.

Conversely, if your pump is too small, you’ll end up never getting your pool up to temperature, no matter how long you run the heat pump for.

Always get advice from a qualified professional on what size of heat pump you require, and err on the larger side to be safe.

13 July 2016

How Much Does a Ground Source Heat Pump Cost?

Ground loop diagram — Representation of a ground source heat pump system.

Ground source heat pumps are growing in popularity as more people want to do the right thing for the environment. They are not necessarily the cheapest option, but look beyond the initial price tag and consider the longer-term savings before making your decision.

So, what do you need to consider?

Remember to include all the costs and savings

Cost is clearly an important question when you are looking at the different options for heating your home or commercial premises. Ground source heat pump costs can be deceptive because they require a larger upfront investment than some other forms of heating.

But don’t be too short-sighted in your calculations, because although the upfront costs can be considerable, ground source heat pumps often operate more efficiently than some of the other options available, which translates into savings down the road. Payback periods for ground source heat pumps can be as quick as 4 or 5 years.

How price sensitive are you?

Be clear from the beginning about how much contingency you have allowed in your heating budget. If you are very sensitive to increases in your budget, you could be exposing yourself to risk if there are complications with the ground works. Ground source heat pumps require pipework to be installed underground, and until the hole has been dug, there is no cheap and reliable way to establish exactly what is down there.

For example, bedrock could be very shallow, making it harder to excavate the trench for the pipes comprising the heat collection system (called the ground loop). Or in the case of a borehole, you might find yourself dealing with unstable ground conditions requiring more support for the borehole than was anticipated. Then there’s always the risk of encountering unexpected services such as sewer pipes or electricity cables, which can get in the way and, if you are unlucky it’s possible that these could be damaged, resulting in expensive remedial work. However, if you use a trustworthy contractor this shouldn’t be an issue.

At least with an air source heat pump, or even a conventional fossil fuel fired boiler, you will have a good idea how much it will cost to install. There are fewer variables that could cause difficulties and higher costs, which make them a safer option if your budget is constrained.

How “green” are you?

An important consideration that doesn’t get talked about very much is how committed you are to a heat pump system. If you are passionate about the technology itself or the benefits that it offers in terms of reduced environment impact, then you will probably be prepared to pay more compared to someone who is just interested in the savings that a heat pump system can offer.

Remember the grants that are available

The Renewable Heat Incentive (RHI) scheme is a government scheme that pays people for generating heat from renewable means. The scheme is run by Ofgem (the Office of Gas and Electricity Markets), which is a non-ministerial government department and an independent National Regulatory Authority. Ofgem protects the interests of gas and electricity consumers and pays those who generate heat under the RHI scheme using the Treasury’s funds.

The payment per kWhr for the generation of hot water and heat under the RHI depends on the size and specifics of the system being used. It will normally be a few pence per kWhr, which doesn’t sound like much, but you might be surprised to know that, over the course of the 20-year life of the payment, a typical system makes a profit, which brings me to my next point.

Don’t forget to factor in the savings over the lifetime of the system

A typical ground source heat pump system will last more than 20 years, which is plenty of time for the savings made on the running of the system compared with a combustion-based system to offset the installation costs. Look at the entire life cycle of the system to understand the overall savings or indeed profits that will be made by the system.

So how much will a ground source heat pump typically cost?

The answer is obviously, “it depends”, but as a general indication, the estimates given below should give you a rough idea. They are broken down into upfront and running costs.

Upfront Costs

Upfront prices for a 10kW system can range between £6,000 and £15,000. This price bracket doesn’t include the connection to the distribution system, which is obviously different for each building and location.

Running costs

Again, running costs will vary according to a number of factors, the most obvious being the efficiency of the heat pump system. Efficiency is normally stated as the coefficient of performance (CoP). The CoP is simply the ratio of units of heat output to the units of electricity used to run the system.

Typically, most systems will have a CoP somewhere between 3 and 4. This is influenced by the difference in temperature between the heat source (the ground loop) and the heat sink (your heat emitters, such as radiators or underfloor heating).

The highest efficiencies will be achieved by low temperature applications such as underfloor heating, particularly if the climate is releatively mild, or if geothermal energy is producing high temperatures in the ground loop (e.g. a hot spring).

Conversely, heating hot water for use in showers, baths etc will result in lower efficiencies. Better efficiencies are always achieved by low temperature applications.

To give a rough guide, a system running at a CoP of 4 would result in 4kWh of heat being produced for each kWh of electricity used. So, assuming an electricity cost of 16p/kWh, such a system would cost 4p/kWh to run.

Add in the RHI savings that are available, and the savings increase even further.

In conclusion

The decision of whether a ground source heat pump is right for your budget or not is not straightforward, but it isn’t that complicated either. Just bear in mind the points above, be clear about your budget, the lifetime cost of the system (including both installation and running costs) and research the grant funding that is available through the RHI incentive scheme, which sadly is coming to an end at the end of March 2022.

With those facts in mind, a calculator and a cup of coffee, you’ll be able to reach the right decision for your particular circumstances.