Underfloor Heating Cost Calculator

Electric underfloor heating (mat or cable) is cheaper to install (£40 to £50 per square metre) but more expensive to run. A 20 sq m kitchen with electric mat at 150 W per square metre, on for 8 hours a day at 28p/kWh, costs around £6.70 a day in winter and roughly £450 over a heating season. Wet systems with a boiler cost £80 per square metre installed plus the boiler itself, but run at roughly half the cost of electric because gas is around a quarter of the per-kWh price.

The fastest payback equation favours wet systems for whole-house installs and electric for single-room retrofits like a bathroom or kitchen extension. A 6 sq m en-suite at electric mat costs around £300 to install and £80 a year to run; replacing a radiator there is overkill. A whole ground floor at 50 sq m running 8 hours a day on electric would cost £1,500 a year - territory where wet systems win clearly.

Wet underfloor heating paired with a heat pump (COP 3.2) runs at roughly a third of the cost of electric underfloor in the same room, because each kWh of electricity moves 3.2 kWh of heat. Install cost is highest (£100 per square metre for the floor plus £8,000 for the heat pump) but running cost is the lowest of any underfloor option. Over a 25-year system life, heat pump underfloor often beats every alternative on total cost.

Insulation under the screed is non-negotiable. A typical UFH install loses 30 to 40 percent of heat downwards into the floor structure if there is no insulation board (50 to 100 mm of PIR rigid foam) underneath. The £5 to £10 per square metre that adds is the single best efficiency upgrade you can specify. For the wider heat-source comparison, [Boiler vs Heat Pump Calculator](/boiler-vs-heat-pump-calculator) covers the system choice in more depth.