Hot Water Floor Heating

  • Discount Kit GFT Open CRES Manifold

    Open CRES Manifold

    £100.00 £95.00 £114.00 incl. VAT
    Low Temperature
  • Discount Kit Plastic Manifold for Heating and Cooling
    Save 70%

    Open Plastic Manifold

    £535.83 £160.83 £193.00 incl. VAT
    Low Temperature
  • Discount Kit Euroconus Connection Fittings

    Euroconus Connectors

    £3.50 £2.87 £3.45 incl. VAT
    Per 2 pcs
  • Discount Kit GFT / Reliance CRES Manifold, incl. Pump

    CRES Manifold, incl. Pump

    £311.67 £285.00 £342.00 incl. VAT
    High Temperature
  • Discount Kit Compact Steel Manifold

    Compact Steel Manifold

    £220.83 £204.17 £245.00 incl. VAT
    High Temperature
  • Discount Kit Floor Heating-Direct Pressure Relief Valve
    Save 55%

    Pressure Relief Valve

    £54.17 £24.58 £29.50 incl. VAT
    15mm or 22mm
  • Discount Kit Temperature Control Unit

    Blending Valve

    £270.83 £216.67 £260.00 incl. VAT
    With A Rated Pump
  • Discount Kit PERT Heating Pipe
    Save 44%

    PE-RT Heating Pipe

    £58.33 £32.42 £38.90 incl. VAT
    10, 14 or 16mm
  • Discount Kit PEX ALU PEX Pipe

    PEX-AL-PEX Heating Pipe

    £104.17 £83.12 £99.75 incl. VAT
    16mm or 20mm
  • Discount Kit Watts Actuator

    Watts Actuator

    £14.58 £13.12 £15.75 incl. VAT
    Connection: M30x1.5
  • Discount Kit Floor Heating-Direct Castellated Insulation
    Save 46%

    Castellated Insulation

    £208.33 £112.47 £134.97 incl. VAT
    With EPS insulation
  • Discount Kit Tacker Insulation Plate
    Save 23%

    Tacker Insulation

    £91.67 £70.42 £84.50 incl. VAT
    20mm or 30mm EPS


Heating a home by underfloor heating can be done in almost any type of property and can be easily installed into both existing and newly installed central heating systems. Floor Heating-Direct supplies a wide range of products that will allow you to successfully install underfloor heating in every room.

About underfloor heating

Heating a home with a water based system works by laying a series of hot water pipes in your floor construction; basically turning a floor into a giant radiator. The pipework that runs the system is connected to the existing heating system by means of a manifold. The manifold serves as the heart of the water heating system and works by the flow of water that is fed from the boiler. Instead of high temperature water being required, as in conventional heating systems, lower temperature water can be used due to the fact that the heating surface is much bigger and unlike a conventional heat source it does not need to give off as much heat per square meter in order to heat a given space to a required temperature.

Underfloor heating manifold

Warm water supplied from the boiler passes through a valve and into the manifold, which then in turn draws water from the underfloor heating pipes. Colder water from the pipework is then mixed with the warm water from the boiler and passes through a heat pump and temperature sensor, that controls the flow of warm water from the boiler that is let into the manifold . If the water passing along the temperature sensor is detected as being warmer than the temperature that has been set by the sensor, the zone valve will close.

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Underfloor heating pipes

Almost all modern pipes for underfloor heating systems are made of cross-linked polyethylene that is formed into tubes. These polypipes are predominantly used in building services pipework systems, heating systems, domestic water piping and insulation for high tension (high voltage) electric cables.

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Fitting underfloor heating

Wet underfloor heating systems
Water underfloor heating systems which are laid into the screeded subfloor are the oldest form of modern radiant floor systems. The pipes can be embedded in a thick concrete foundation slab or in a thin layer of concrete or other materials installed on top of a subfloor. 

Dry underfloor heating systems
In so-called "dry" floors, heating pipes run in an air space beneath the floor. For this type of system, reflective insulation must be installed under the pipes to direct the heat upwards. 
Heating pipes may also be installed from above the floor, between two layers of subfloor. In this case the pipes are fitted into aluminium diffusers that spread the water's heat across the floor in order to heat the floor more evenly.

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Insulation for underfloor heating

Insulation should be considered an integral part of your underfloor heating system. If the subfloor, you are laying your system onto, does not have insulation beneath it will be necessary to place insulation directly beneath the heating system to ensure manageable heat up times and to minimise running costs. The better the insulation of the floor, the better the output and warmth of the floor heating system which means better energy efficiency.

Installing underfloor heating

Bifilar Pattern
Preferred Pipe Lay Out

Preferred underfloor installation

In order to get the best results with an underfloor heating system you need to ensure even temperatures throughout the floor area. When the flow and return pipes are situated next to each other, the floor is warmed up equally. The water runs through the pipes and releases its heat. The cooled water runs back to the manifold.

This technology gives the most economic floor heating system and is the preferred underfloor installation.

Meander Pattern
Pipe Lay Out

Another underfloor installation

Flow and return pipes are not situated next to each other and will therefore not allow the floor to be warmed up equally. This might, however, be preferred when underfloor heating is installed in rooms with cold outer walls or large windows. When making use of this lay out the first part of the flow pipes (the first meters of pipe) are to be placed along the coldest wall.

Heating pipe spacing

When planning the lay out for your underfloor heating system it is advisable that you use 100mm spacings between the pipe centres for main heating and 150mm spacings for comfort heating. Obviously, as you alter this measurement it effects the heat output in that area.
Whilst the spacing between pipe centres is recommended at 100mm or 150mm, the recommended distance between pipe and wall is 100mm. 

Underfloor installations and floor covering

Underfloor heating systems can be used for almost any floor finish, but different floor finishings have different levels of thermal resistance.
Tiles, stone, marble and slate floor finishings have a low level of thermal resistance and allow rapid thermal movement. Usually these type of finishings are excellent emitters of thermal energy and will provide optimum efficiency over an underfloor heating system. 
Carpet, wood and laminate floors have a higher level of thermal resistance and will slow down thermal movement. Therefore these type of finishings require a reflective foil or diffuser plates, usually made of aluminium or steel and placed underneath the heating pipes, to ensure proper heat diffusion.

Thermostats and zone control for underfloor heating (individual temperature settings per room)


Each of the manifolds supplied by Floor Heating-Direct operates by means of one single temperature control unit, which controls the flow of water from the boiler to the underfloor heating system and adjusts it to a uniform temperature.  Should you prefer to individually control the temperature of each zoned area, you require electronic thermic actuators to operate and control individual rooms.

Each thermic actuator is mounted on the fluid shut-off valve and connected to a control unit, which is operated by a wireless thermostat, allowing you to set different temperatures for each zone as desired.