What does underfloor heating cost to run?

Electric floors are rated at full power, but a thermostat switches them off once the floor is warm. This estimate allows for that.

Which kind of underfloor heating?

Heated floor area (m²)A small bathroom is about 3 to 5 m²

Hours switched on a day

Days a year (optional)For a yearly figure, such as 150 for the colder months

Change assumptions

Mat rating (watts per m²)Example value. Check your mat or cable's label or manual.

Share of time heating (%)The thermostat switches it off once the floor is warm; 100% means it never does

Your electricity unit rate (p/kWh)Cap: 26.32p

Estimated cost a day

47p

1.8 kWh a day, with the floor heating 60% of the 4 hours.

Upper limit if it never switched off: 79p a day (0.75 kW for 4 hours). Real use depends on insulation under the floor, the room temperature and the thermostat setting.

Ofgem price cap, GB average, Direct Debit, 1 Oct – 31 Dec 2026. Electric floors suit small rooms that need warming quickly, such as bathrooms; Energy Saving Trust notes they are costly to run over long periods or large areas.