Worked examples: Browse pre-calculated scenarios at heat-pump-vs-gas, then return here to replace the assumptions with your own figures.
How this calculator works
- A heat pump multiplies electrical input by its coefficient of performance, so the relevant comparison is cost per kWh of useful heat rather than the headline electricity unit rate.
- The gas side adjusts the gas unit price for boiler efficiency because not every kWh of gas becomes useful heat inside the home.
- The annual comparison applies those useful-heat costs to the heat demand you enter.
What can change the result
- Seasonal rather than headline heat-pump COP
- Your actual electricity and gas unit rates
- Boiler efficiency and annual heat demand
- Any gas standing charge that disappears if gas is removed entirely
How to read the result
A small difference in assumed seasonal COP can materially change the result. It is worth checking the comparison at a lower and higher COP before using it to assess a quotation.
A useful way to stress-test the answer is to change the most uncertain input by 10 to 20% and see whether your decision still looks sensible.
Worked example
At a COP of 3.2, each kWh of electricity can provide about 3.2 kWh of useful heat, while a 90% efficient boiler needs more than 1 kWh of gas input for each useful kWh delivered.
Frequently asked questions
Why is COP so important?
A small change in seasonal COP can materially change annual electricity use.
Does this include standing charges?
No. If removing gas entirely removes a gas standing charge, consider that separately.