With energy prices still being relatively high, you may wonder if it’s cheaper to use an electric heater to heat your entire house rather than a gas boiler.
First, there is a big difference in the unit costs of gas and electricity. If we take Ofgem’s January 2024 price cap as an example, gas is 7.42p per kWh, compared to 28.62 per kWh for electricity. This means it will cost £1.78 to run a 24 KW gas boiler at full power for an hour, while a 2 KW electric heater would cost 57p to run.
However, if you are trying to heat more than one room in your house, an electric heater will not be a particularly economical option.
In contract, modern condensing boilers have efficiencies in excess of 90%, and they rarely need to work at full power for an extended period. For example, if you set your thermostat to 20 degree Celsius, the boiler will only come on to heat the radiators to maintain this temperature, meaning it can be idle or running at low power much of the time. This is especially true if you have a good level of home insulation. Moreover, not heating rooms can lead to damp and mould forming, so a better compromise would be to run your central heating but turn down the radiators in less frequently used rooms.