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Underfloor Heating Systems

The perfect partner for an Air Source Heat Pump is Underfloor Heating. This is because Air Source Heat Pumps are more efficient the lower the water temperature and as Underfloor Heating operates at lower temperatures than radiators, it is clear why it is a perfect match.

How does underfloor heating work?

Underfloor heating is a system that circulates warm water in the floor to provide a much kinder, more even room temperature. It works by using radiant heat to warm up the floor, which then warms up the air around you.

Underfloor Heating has a more even distribution of heat since there is pipe in the floor evenly spaced that emits a nice gentle warmth that gives a warm floor which gets cooler at ceiling height. Underfloor Heating is typically more efficient than radiators, as it operates on lower temperatures and it also frees up valuable wall space.

There are a number of installation options available and at Unitherm, we have the solutions to meet with the building. These systems are a great way to lower your carbon emissions and therefore reducing your carbon footprint.

Please find detailed below the floor construction details and core components for Unitherm’s range of warm water underfloor heating systems:

Our range of underfloor heating systems


The Uni-staple system provides a quick, flexible and simple method of securing the underfloor heating pipework when laying a screed floor. The staples have a barbed end which fixes into the insulation. To speed up the process further, a pipe stapler is available. In preparation for certain screeds, a polythene sheet/membrane may be required over the insulation prior to stapling the pipe.


The Uni-Cliprail system provides a quick, flexible and simple method of securing the underfloor heating pipework when laying a screed floor. The cliprail has an adhesive back which fixes onto the insulation. In preparation for certain screeds, a polythene sheet/membrane may be required over the insulation prior to stapling the pipe.

Uni-Spider25 / Uni-Spider Slim20

The Uni-Spider25 / Uni-Spider Slim20 system comprises of a series of interlocking castellated panels which have been designed to avoid using cliprail and staples to speed up the installation of the underfloor heating system. It has an adhesive layer on the underside to ensure no movement when the screed is poured. This design enables very thin screeds to be poured over the panel to give the lowest possible build.


The Uni-Foilboard20 is a low profile, light weight system, ideal for all types of installation especially where the floor height is a premium. The insulation panel is pre-grooved, a foil reflective layer is then heat-adhered to produce an effective high output panel. When using carpet or a thin laminate, a 6mm flooring grade plywood would need to be used.


The Uni-Gyspum18 is a low profile high performance system manufactured from reinforced gypsum, the CNC routed panels with universal bulb returns are engineered to provide an optimum heating system. There are significant installation time saving benefits over that of a wet system. A flexible adhesive should be used when installing tiles.


The Uni-Foilchip22 is a structural heating board which gives rapid even heat distribution, dry construction and is fully recyclable. With a 22mm thickness, a 6mm flooring grade ply would need to be bonded and mechanically fixed to the chipboard prior to any floor covering. This can be installed on solid, joisted and battened floors.


The Uni-Joistplate is a double channel aluminium diffuser plate which sits between joists. When notching joists, this needs to be done in accordance with the relevant building regulations. Web/Eco joists & I-beams can be utilised without the need to notch the joists. This design is ideally suited for new build applications.


The Uni-Pugscreed can be used with either just staples or you can install cliprail for extra security of the pipe. The screed density can vary depending on the thickness of screed installed. When installing intoa joisted floor system, the joists must be correctly sized to accept the additional loading. Battens can be installed onto a solid floor to reduce the screed thickness.

PEX-b 16mm; PE-RT 12mm

Our multi- layer underfloor heating pipe comes with a 50 year warranty and conforms to ISO 9001 & DIN 4726. Both our 16mm & 12mm are available in various coil lengths. We would recommend the user of a De-Coiler when using the larger coils.

Uni-Mix LV

The Uni-Mix LV is designed to blend flow and return from your heat source to provide a constant floor temperature throughout. With an operating range of 30-65° and featuring a fully ERP compliant, energy efficient circulator as well as a port for an automatic air vent. Also, it comes with a compact bolt on the unit which provides a quick and simple installation.

Dynamic Balancing SS Manifold

Stainless steel manifold for UFH systems with dynamic flow balancing and independent setting for each individual circuit, consisting of:

  • Delivery manifold with flow meters with fluid shut-off function
  • Return manifold with dynamic flow balancing valves and manual handwheel (M30 x 1,5 mm connection), prearranged for thermo- electric command via R473/R473M actuators that can be installed after fitting the relative R453FY002 ring nut (to be ordered separately)
  • Pair of end pieces with self-sealing, complete with drain cocks, manual air vent valves and specific R74 key
  • R588Z metal brackets
  • R73PY010 key for presetting

Floor Coverings

Please see detailed below, details on typical floor coverings when used in conjunction with a Unitherm underfloor heating system:

Carpet – The combined tog value of the carpet and underlay should NOT exceed 2.5 tog, but its preferential for the combined tog value to be below 2.

Solid Wood – Solid hardwood should be kiln dried with a minimum moisture content of between 6% - 9%. The hardwood should also be stored in a dry place, acclimatised prior to laying and a floor sensor fitted to avoid overheating.

Laminate – A more stable floor covering than solid wood and its more hard wearing. Laminate can be easily installed on underfloor heating as a floating floor or with an adhesive, but check with the supplier for installation instructions. The floor temperature should not exceed 27°C, so a floor sensor should be fitted to avoid overheating.

Vinyl – Whilst vinyl works well with underfloor heating, it should be noted that the floor temperature should not exceed 26°C and therefore a floor sensor should be fitted. Also, vinyl should be acclimatised prior to installation by unwrapping and it being loose laid in the room that the vinyl is to be fitted for at least 24 hours prior to fixing.

Tiles – A very common floor covering with underfloor heating. Since tiles conduct heat well, the underfloor heating system will operate more efficiently and heat the room quicker. A decoupling membrane is recommended, as this will isolate any movement and therefore protect the tiles from cracking.

For more information about our underfloor heating systems, please download our Datasheet.

Benefits of underfloor heating systems

  • Energy efficient – Underfloor heating is a very energy efficient way to heat your home. It also saves on heating bills and reduces carbon emissions.
  • Comfortable – Underfloor heating system can be installed in any room of your house, including bathrooms, kitchens, living rooms, bedrooms and conservatories. This means you can enjoy warm comfort wherever you are in your home.
  • Durable – The underfloor heating system will last for many years without requiring maintenance.
  • Environmentally friendly – Underfloor heating is much more environmentally friendly than other forms of heating, such as radiators and wood burning stoves. This means that you can help reduce your carbon footprint by installing underfloor heating.
  • Safe - If you have children or pets, underfloor heating is perfect for them too. It's discreet and hidden design means there is no danger, so you don't need to worry about where you install it.
  • Flexible – It can be installed anywhere in your house, including bedrooms, living rooms, kitchens and bathrooms.

Is underfloor heating expensive to run?

Underfloor heating can be expensive to run, depending on the type of system you installed and the size of your home.

However, it is a very energy efficient way to heat your home and can save you money on fuel costs in the long run.

Running costs for underfloor heating depend on the system installed, as well as the size of your home. Generally speaking, underfloor heating is more expensive to install than other forms of heating, such as radiators and wood burning stoves.

Underfloor heating systems are designed to be energy efficient and use less electricity than traditional radiators. They also provide an even distribution of heat throughout the room. This way, you can enjoy comfortable temperatures without having to turn up the thermostat too high.

Additionally, underfloor heating systems require minimal maintenance and can last for many years without needing any repairs or replacements.

What is the best way to control underfloor heating?

The best way to control underfloor heating is to use a thermostat. A thermostat allows you to set the desired temperature for your room,l automatically adjusting the heating system accordingly. This ensures the room is kept at a comfortable temperature, without having to manually adjust the settings.

You can also use a programmable thermostat to set different temperatures for different times of the day. This allows you to save money on energy bills when you’re not at home.

Is underfloor heating more efficient than radiators?

Underfloor heating is an energy-efficient and cost-effective alternative to radiators. When properly installed, it can use up to 25% less energy than a radiator and up to 40% less when used with a heat pump.

Not only that, it also provides even heat distribution throughout the room, as well as gentle warmth which makes it more comfortable to walk on. Overall, underfloor heating is a great option for those looking for an eco-friendly solution to provide consistent warmth in their home.

Should I leave my underfloor heating on all day?

Whether you should leave your underfloor heating on all day depends on your individual needs and preferences. If you are looking to save money on energy bills, it’s recommended to only turn on the system when necessary.

You can set the thermostat to a lower temperature during the day when no one is home. Then, in the evening, you can turn it up just before everyone arrives back.

What is the lifespan of underfloor heating?

The lifespan of underfloor heating systems vary depending on the type of system installed and how well it is maintained. Generally speaking, underfloor heating systems can last for up to 25 years with proper maintenance.

Note that the lifespan of an underfloor heating system may be shorter if not properly maintained. Regular cleaning and servicing of the system can help to ensure it runs efficiently and safely, and can extend its lifespan.