Electric Heater vs Heat Pump Cost Calculator
Compare what it costs to get the same heat from a resistance heater and from a heat pump, the same way an air conditioner works in reverse.
Last checked 10/11/2026. Sources: Ofgem: Energy price cap unit rates and standing charges.
Guide
How the cost is worked out
A resistance heater turns each kWh of electricity into 1 kWh of heat. A heat pump moves heat, so each kWh of electricity delivers several kWh of heat. That ratio is the coefficient of performance (COP). Electricity needed = heat wanted ÷ COP.
Example. 2 kW of heat for 6 hours a day over 120 days is 1,440 kWh of heat. A resistance heater uses 1,440 kWh. A heat pump with a COP of 3 uses 480 kWh, a third as much.
COP is an editable assumption
A COP of 3 is an editorial rule of thumb. Real COP changes with the outside temperature and the model; the model’s data sheet gives its rated figure. Enter the real figure if you have it.
Using it for cooling
Air conditioners are heat pumps too. Enter the cooling you need in kW and the unit’s rated efficiency, and ignore the resistance comparison.
What is not included
Installation costs, insulation, standing charges and gas heating are not included. The default rate is the Ofgem price cap electricity unit rate for 1 October to 31 December 2026.
Common questions
Is a heat pump cheaper than an electric heater?
Per unit of heat, yes. At a COP of 3 it uses about a third of the electricity, so it would save about two thirds of the running cost.
What is a good COP?
It depends on the model and the weather. Check the data sheet for the figure at your design temperature.
How do I know how many kW of heat I need?
A heating installer can size it from the room or home. The tool lets you try different figures.
Does this include gas?
No. It compares two electric options only.
What next?
- Is a heat pump worth the up-front cost? Work out the payback. Energy Upgrade Payback Calculator
- Doing the work yourself? Plan the materials with Handyfig