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Electric Underfloor Heating Running Costs

The cost of running an electric underfloor heating system varies in each installation, based around the level of insulation and heat loss, running temperatures, your heating program and the type of room the system is installed in.

The table below provides some general guidance about the likely daily running costs (in pence) of a Thermonet EZ 150W/m² system used as a primary heat source.

Time On (Hr)1m²2m²4m²5m²10m²15m²25m²
1 2.1p 4.2p 8.4p 10.5p 21.1p 31.6p 52.7p
2 4.2p 8.4p 17.0p 21.1p 42.2p 63.2p 105.4p
3 6.3p 12.6p 25.3p 31.6p 63.2p 94.8p 158.1p
4 8.4p 17.0p 33.7p 42.2p 84.3p 126.5p 210.8p
5 10.5p 21.0p 42.2p 52.7p 105.4p 158.1p 263.4p
6 12.6p 25.3p 50.6p 63.2p 126.5p 189.7p 316.1p
7 14.8p 29.5p 59.0p 73.8p 147.5p 221.3p 367.0p
8 16.9p 33.7p 67.4p 84.3p 168.6p 253.0p 421.5p

 When calculating these approximate costs* the following assumptions were made:

  • System is installed in a house built to current Part L regulations regarding fuel and power conservation.
  • Thermonet EZ 150W/m² installed under 8-10mm ceramic tiles
  • A layer of 10mm econoboard insulation included in the floor build up.
  • Heat up times are included in the “Time On”.
  • Electricity price of 14.05p/kWh – average UK price in Feb 2015.


Key factors affecting underfloor heating running costs

Insulation - Boost efficiency by as much as 50%

thermonet electric underfloor heating running costs

Effective substrate insulation, such as Econoboard, reduces downward heat loss and provides faster heat up times. If your system reaches the desired temperature more quickly it does not need to call for heat for such a long time, which has a dramatic effect on your running costs.

We estimate that installing a layer of our 10.5mm insulation board will improve the efficiency of a Thermonet electric underfloor heating system by as much as 50% when compared with an un-insulated concrete substrate.

Room Height

Some rooms are taller than others, which means they have more air volume compared to a room with identical lateral dimensions. Generally the higher the ceiling, the more energy is needed to heat the room. Electric underfloor heating is a much more efficient way to heat a room with high ceilings as the heat radiates into the room from the floor up, providing a comfortable even heat signature.

A traditional radiator would heat the top of the room first, wasting a lot of energy in vaulted ceilings, whereas electric underfloor heating warms the area that people use making it more efficient.

Heat Loss

Draughts, extractor fans and poor insulation cause heat loss which the heating system must compensate for. This results in the electric underfloor heating system to work harder, for longer which has an adverse effect on efficiency and your heating bills.

Be sure to install Econoboard insulation with every electric underfloor heating system to provide adequate substrate insulation and improve your running costs by as much as 50%.

Heating Program - Use a programmable thermostat

An efficient, personalised heating program or schedule will ensure your electric underfloor heating system is only on when you need it, minimising wasted energy. 

The UK's first dual control electric underfloor heating thermostat

Thermotouch 4.3dC makes it easy to set a customised heating schedule to ensure you're not wasting energy heating an empty house. It's so easy to use that you won't even need a manual!

Our 5259 Touchscreen programmable Thermostat is an attractive addition to any room and provides a fully programmable 7 day, 6 event heating program that you can schedule around your daily routine.

Comfort and Economy temperatures

Thermogroup UK recommend a Comfort (or “On”) temperature of 23-25°C and an Eco (or “Off”) temperature of 18°C.  Operating between these temperatures will maintain an economical minimum temperature and maximise comfort and efficiency. Our 5259 Touchscreen programmable Thermostat is a fully programmable option and allows for a customised heating schedule to help you achieve an efficient and economical electric underfloor heating system.

Interested in underfloor heating?

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*Please note that these approximate running costs are for illustrative purposes only and do not imply any warranty or guarantee as regards energy consumption and/or running costs. All information on this page including but not limited to the electric underfloor heating running costs is a copyright of Thermogroup UK and should not be copied or used without written permission from Thermogroup UK.