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Underfloor heating

Underfloor heating covers a larger surface area and ultimately allows you to run the underfloor at lower temperatures and reduce running costs with no adverse effect on comfort.

The best heating solution

Anyone with underfloor heating will tell you that they get more comfort from their heating system because it provides warmth from the the ground up, basically the heat is exactly where you need it most. 

Water Underfloor Heating

Water Underfloor Heating is a very efficient way of heating your home. The flow temperature required to run through underfloor heating is around 45°C, rather than the 60°C+ that a standard radiator system require, so your heat source doesn’t have to work as hard to meet the demand.

Holistic system

At Harvest we wont specify by rule of thumb and install at 200mm -300mm centres we will carry out a room by room heat loss which will illustrate to you and us exactly how many Watts are needed to deliver the heat for each particular room. This can often mean that closer centres are needed at 150mm. By carrying out a heat loss report we will be able to offer different running temperatures that will lower your running costs and make your system run very efficiently. 

Water Underfloor Heating

Underfloor heating design

At Harvest we design the underfloor to a plan and a specification that will provide the right level of heat for the room, we will produce a design that will then be sent to the client for approval. The design is very important because areas like under baths, showers, fitted wardrobes and fire places are avoided but need to be compensated for in other areas. All of the pipework will run back to a manifold at an agreed spot.

Preparation for underfloor heating under a liquid screed floor

Screed roller

Insulation is the most important part of of the preparation for underfloor heating.  Without adequate insulation levels, the heat from your underfloor tubes may be lost downwards instead of transferring upwards.  Above the insulation there needs to be a plastic membrane which is taped together to form a complete barrier to hold the screed that is to be poured. Alternatively a plastic crate can be used to take the underfloor (please see picture).

Screed is typically 50mm for domestic properties, it is important that the drying out of the screed is done correctly, typically the ratio for drying out is 1mm per day (50 days for a 50mm screed). This time can be reduced if your new heating system has a screed drying setting. 

On the ground floor and in most cases, at least 100mm foil-backed hard insulation such as Kingspan or Celotex will do the job. However, if you are limited for depth there are low board systems which are as little as 16-22mm. The low boards systems are not quite as efficient, but still do a very effective job in insulating the ground

First floor underfloor heating

In many properties there may be joists on the first floor. These joists are often set at 400mm centres and for this we typically use a plate system. It is important that the underside of this plate is well insulated so that the heat transers upwards instead of downwards. The preferred method for this is rigid insulation that is then braced underneath. A low board system is used over an existing floor where there is limited space.

First floor underfloor heating

Mixing radiators and underfloor

Underfloor heating is more expensive than a standard radiator system and for this reason many of our clients have underfloor downstairs and radiators upstairs. The majority of households spend most of their time downstairs in warmer temperatures of 21°C, whereas upstairs in bedrooms, design temperatures are slightly lower at 18°C. Radiators upstairs can be a very cost effective and a resourceful combination to a downstairs underfloor system. 

Mixing radiators and underfloor

Floor coverings and underfloor heating

Stone and ceramics 

Hard surfaces such as stone and ceramic transfer the heat most effectively. However wooden and carpet floors coverings are also fine with underfloor, but it should be specified at design to get the most out of your underfloor.

  • Ceramic tiles
  • Limestone
  • Slate
  • Flagstones
  • Marble
  • Polished screed


Engineered wood is the best option for underfloor heating as it is stable enough to perform well with changing temperatures. With solid woods (hard or soft) extra care must be taken in specifying board width and depth.

  • Engineered wood
  • Solid hardwood
  • Softwoods
  • Parquet
  • Bamboo

Laminates, vinyl and rubber

These products perform very well with underfloor heating but check manufacture’s recommendations for maximum floor surface temperature to ensure it can be used with your underfloorheating.

  • Vinyl
  • Amtico
  • Linoleum
  • Laminate tiles
  • Rubber

Carpet and other natural coverings

Carpet and underlay with a total Tog value of 2.5 or less can be used well with underfloor heating. Any thicker than this and the carpet will stop sufficient heat reaching the room by acting as a insulator. Our design calculator will factor in additional demand if a a carpet is specified.

  • Carpet 
  • Cork
  • Coir

Thermostat Control

Control of the underfloor is slightly different to conventional heating, this is because each zone or room can be controlled individually via a thermostat. So different temperatures can be achieved rather than one temperature in a number of rooms. We supply thermostats that can be controlled in the home and remotely so the heating can be controlled away from the home via computer,tablet or smart phone. 

For a quotation and advice please do not hesitate to contact us.