Through our research on the provision of underfloor heating for heat pumps, we understand that when considering underfloor heating you will have certain questions. Based on our research, we have compiled this underfloor heating FAQ to provide answers to some of the most regular questions we receive.

Q: Will underfloor heating work with my heat pump?

A: Absolutely. Certified MCS installers can provide you with advice on underfloor heating for heat pumps. We have the skills and experience to ensure your floor heating system is ideally complimented by your heat pump to maximise its efficiency and benefits to you.

Q: At what stage of the project should I install my underfloor heating?

A: This will depend upon the build / renovation schedule of your specific project. Generally, we would advise that the property should be airtight before the floor heating is installed.

Q: How long will my underfloor heating last? 

A: The underfloor heating pipework is typically guaranteed for 25 years but should last well in excess of this, likely outliving the heat pump itself. To ensure the longevity of the pipework and prevent any leaks at a later stage, the pipework should be fully tested during the installation stage to detect any leakage and prevent issues later.

Q: What happens if my underfloor heating develops a leak?

A: In the unlikely event of a leak occurring, it will usually happen at the manifold as the pipes should have been pressure tested before installation. As a result this should make the leak very easy to locate and rectify cost effectively. Other types of system are available, such as warmup underfloor heating, which uses electricity instead of fluid in pipes.

Q: Will underfloor heating restrict my choice of floor finish?

A: The correct floor covering should be carefully considered to ensure heat is not prevented from rising into the room by the floor covering. As you might expect, MCS installers can give expert advice on floor covering to ensure the best results without restricting the design of your home.

Q: Can I retrofit underfloor heating into my property?

A: This is another regular entry on an underfloor heating FAQ. Installation of floor heating is obviously easier within a new build project where a simple screed underfloor heating system can be installed, but if designed correctly, you can still enjoy the benefits of heating your property using underfloor heat on a retrofit basis, using plate underfloor heating for example. Many installers have successfully installed underfloor heating for a range of retrofit projects and shown that this is indeed possible in a cost-effective manner.

Q: What underfloor heating warranties are available?

Understandably, you need to have the confidence that your floor heating system will stand the test of time. Most pipe manufacturers are so convinced by the quality of their product that they offer a standard pipework warranty of 25 years.

Many installers also provide a parts warranty on all the component parts.

In the following video, Allen explains a few more bits and bobs about underfloor heating systems…

Hopefully by the time you reach this page we will have given you some good background information on underfloor heating and answered your questions on what is underfloor heating. It’s now time to consider the advantages of underfloor heating and how a professional installer can deliver them for you.

Advantages of Underfloor Heating – Combines easily with Heat Pumps

One of the major advantages of underfloor heating is the way in which it can be successfully combined to work with heat pumps.  Concentrated heat can be delivered by a heat pump to provide domestic hot water up to 60˚C while feeding the floor heating system at a lower efficient temperature. 

Underfloor heating systems are designed to optimise the efficiency of heat pumps so not only is your renewable energy heating system more efficient overall, it is delivering a constant, controlled heat and can help reduce running costs and your carbon footprint at the same time.

Advantages of Underfloor Heating – No Maintenance

As there are no moving parts to an underfloor heating system, there is little that can go wrong. If correctly installed, pressure testing of the pipes means any potential leaks will have already been identified at an early stage and dealt with prior to screeding or installation of plate underfloor heating. As a result, one more of the advantages of underfloor heating is there are no regular maintenance costs to incur unlike traditional convection heating. 

Advantages of Underfloor Heating – Comfort

One of the many floor heating advantages is that underfloor heating heats the whole floor area in which you live. This generates the opposite heat cycle to that of conventional heat sources and results in warm feet and consistent room temperatures. Compared to conventional radiators, an underfloor heating system generates more radiant heat as opposed to convective heat.

Advantages of Underfloor Heating – Freedom of room design

Another example of underfloor heating advantages is that floor heating allows you the freedom to design your room layout without compromise. You have the flexibility to locate your furniture where you wish, suiting your lifestyle needs and not your heating system as no space is lost to radiators.

Advantages of Underfloor Heating – Flexible Controls

Unlike traditional convection heating systems which are often controlled by a single thermostat, a floor heating system provides the flexibility to control individual rooms via thermostats. These can be easily programmed to meet the demands of a particular area instead of wasting energy and money heating areas of the property which are used less often than others.

Advantages of Underfloor Heating – Safety

With lower flow temperatures and no protruding radiators, installing and using a floor heating system means there is no longer a risk to small children and other vulnerable groups sustaining injury through burning.

Advantages of Underfloor Heating – Health & Well Being

Floor heating advantages are also demonstrated by the fact that an underfloor heating system produces less airborne dust than the amounts associated with radiators and convection currents. This is a real plus for asthma sufferers and people with allergies. Warmup underfloor heating is a good option for retrofitting underfloor heating.

You can find more useful information regarding underfloor heating in our underfloor heating FAQ. Or watch the following video for even more advantages of underfloor heating.

What are Plate Underfloor Heating Systems?

Plate systems can be used with timber suspended floors where a screed underfloor heating system would not be suitable. A mechanical fixing is required for a wooden floor. The system requires insulation to be fixed between the joists, tight against the underside of the plate to prevent the downward passage of heat. Just because you have a wooden floor that doesn’t lend itself to a screed system doesn’t mean you have to miss out on all the advantages of underfloor heating.

Typically the first preference is to cross batten at 400mm centres, however if you are experiencing height restrictions, fixing direct to the joists would be an alternative.

Aluminium plates are then fixed to the joists with 16mm PEX pipe neatly fastened within to aid the in the conductivity of the heat. They come in lengths of 1250mm and when laying the plates, you should leave a minimum of 50mm between each plate.

Notching is required in order for the pipe to pass over the joists. This must be carried out by a competent person. You should allow a 20mm x 20mm notch for each pipe.

What Plate Systems are Available?

There are a variety of underfloor heating systems suitable for Standard Plate installation both on a bespoke or kit form basis. Different systems are available for use with heat pumps or boilers and full specifications can be provided on request. Take a look at our underfloor heating FAQs for answers to many of the common questions you might have about the different approaches that can be taken.

Cross Battened Plate

This system is traditionally installed onto 20mm battens which lay at 90 degrees to the existing joists or on a decked floor at 400mm centres. The heat is transmitted in the same way as a Standard Plate system using aluminium plates to span the battens. The system requires insulation to be fixed between the joists as close as possible to the underside of the cross battens and plate to prevent the downward passage of heat.

Cross battening ensures that a uniform distance to suit the diffuser plates can be achieved and negates the need for notching.

Diffuser plates are 390mm wide which naturally leaves a gap in between the plates when laid at 400mm centres. This avoids any noise as the plates expand and contract with heat.

Cross battened plate systems are normally the preference for first and second floors however, on ground floors there is usually a ventilated void so pug would be preferable.

If plates are used, an alternative to the PUG system is routed insulation as this prevents air movement and heat loss.

What is a Cross Battened Plate on Timber Floor Underfloor Heating System?

Plate systems can be used where existing timber decking i.e. ply or chipboard cannot be removed in the instances where screed is not an option. Also best for floor finishes where mechanical fixing is required.

Cross battening ensures that a uniform distance to suit the diffuser plates can be achieved and negates the need for notching.

Diffuser plates come in lengths of 250mm. When laying the plates you should leave a minimum of 50mm between each length of plate. You should also ensure there is a 5 to 10mm gap between the plates where they are stapled to the joists and that no plate edges overlap.

Cross battened plate systems are generally the preference for first and second floors however, on ground floors there is usually a ventilated void so pug would be preferable.

If plates are used, an alternative to the pug system is routed insulation as this prevents air movement and heat loss.

Which Cross Battened Plate Systems for Timber Floors are Available in Scotland?

Many suppliers provide a variety of underfloor heating systems suitable for Cross Battened Plate installation. These systems are available for use with heat pumps or boilers and full specifications can be provided on request.

If your project demands a different approach, it is possible to use electrically heated underfloor systems to do the same job.

What is a Screed Underfloor Heating System?

Screed underfloor heating systems are most commonly used and have the advantage of being the most efficient due to the lower flow temperatures. Insulation is placed on top of a ground bearing slab, block and beam or suspended concrete floor, with a vapour barrier / slip membrane positioned under the floor heating on top of the insulation. This is to protect the screed from reacting with the insulation product.

Cliprail is then fastened to the insulation using cliprail clips with the PEX pip fixed into place using the pipe clips. The cliprail also raises the pipe away from the insulation allowing the sand / cement screed to flow all the way around the PEX pipe, ensuring full conductivity and maximising the thermal mass.

Edge insulation should be laid to prevent a thermal bridge between the screen and the exterior wall. The screed must comply with British Standards Code of Practice.

Additional cliprail, clips and pins will be required if using a flow-screed as the liquid will try to float the pipe. 

Which Screed Underfloor Heating Systems to Choose?

Underfloor heating installers provide a variety of underfloor heating systems suitable for screed installation both on a bespoke or kit form basis. Our underfloor heating FAQs have answers to a lot of the most common questions you might have about which type of system to use.

Flow screed

A Flow Screed system is very similar to a standard screed system but due to the higher density requires additional fixings to fasten the PEX pipe so that the pipe does not float when the screed is installed. Worth noting here is that if you cannot use screed due to the nature of the flooring in any given room, you can use plate underfloor heating for the same effect. Warmup underfloor heating uses electricity to generate its heat and is an alternative you might want to consider.

Screed on Mesh

Screed on mesh is typically fixed onto A412 Builders Mesh using cable ties. The installed system is then covered with a standard screed.

Most systems are available for use with heat pumps or boilers and full specifications can be provided on request.

PUG

This is generally a thinner screed laid between existing joists.

If you would like to know more about underfloor heating, take a look at this article, which explains in more details how such systems are designed and installed.

Many people have heard of underfloor heating but may not necessarily know exactly what it is or may not be aware of the current technology. For example, electrical floor heating was widely used at one time but was inefficient and not cost-effective as although it used cheap night time electricity to provide underfloor heat via electrical cables installed in the floor, the temperature was not easily controlled. This meant very hot floors in the morning which had then cooled down too much to be of benefit in the evening.

Thankfully though, underfloor heating has progressed significantly with the development of a ‘wet’ distribution system and can now be very easily linked to renewable energy systems such as heat pumps.

Underfloor heating may be more easily understood as a large radiator which is easily controlled and transfers heat to the floor space within a room to provide continual, efficient and comfortable heating.

How does Underfloor Heating work?

Underfloor heating provides rising heat by gently warming water which circulates in pipes installed within the floor construction. The water is heated via heat pumps and if the floor heating system detects temperature  rise  is  required through its thermostatic  control, additional heat is passed through a manifold where it circulates before passing once again through the pipes.

The result is a warm and comfortable environment which maximises living space because the room will be free of radiators and unsightly pipework.

Underfloor Heating – system types

Underfloor heating is a whole house solution capable of heating lounge, utility, bedrooms and bathrooms so no matter what the project, floor heating from professional heat pump installers can be designed to meet your specific needs.

Solid Floors – Screed System

This is the most common floor heating installation method for new build properties. Floor Heating Screed systems typically consist of a pre-installed rigid board insulation laid on top of a ground bearing slab, block and beam, suspended concrete floor or timber floor. The fixing system is applied to the insulation to which the PEX pipe can be attached. To complete the floor construction, a screed is applied to envelope the heating system. This type of system relies on the conductivity of the screed or concrete to conduct heat from the pipe surface to the underside of the floor finish.

Suspended Timber Floors

This underfloor heating system will be specified when the property has suspended timber joists instead of a concrete floor. A suspended timber plate system consists of a pre-installed rigid board insulation laid between joints (ideally at 400mm centres). A double channel aluminium heat diffusion plate is then affixed to the top of the joist to which the PEX pipe can be inserted. This type of floor heating system relies on the conductivity of the heat diffusion plates to conduct heat from the pipe surface to the underside of the floor finish.

You can find more useful information regarding underfloor heating in our Underfloor Heating FAQ.