Is a heat pump cheaper to run than a gas boiler?
It depends on the price of electricity relative to gas, and how efficiently each system turns that energy into useful heat. Comparing the price of one kWh of electricity with one kWh of gas misses the heat pump’s efficiency advantage.
Start with the unit rates on your energy bill. In the UK, enter pounds: 30p becomes £0.30 and 9p becomes £0.09. Use your own tariff including the taxes you actually pay. The figures initially shown here are examples, not current market prices.
A worked comparison
Suppose your home needs 12,000 kWh of useful heat a year. At an electricity price of 0.30 and a heat pump SCOP of 4, the heat pump uses 3,000 kWh of electricity and costs 900 a year. At a gas price of 0.09/kWh and 90% boiler efficiency, the boiler uses about 13,333 kWh of gas and costs 1,200. The difference is 300 a year before fixed costs.
Find the break-even efficiency
The energy-only break-even COP is electricity price divided by the gas cost per useful kWh. In this example it is 0.30 ÷ (0.09 ÷ 0.90) = 3. A heat pump operating above 3 costs less in energy; below 3, gas costs less. At exactly 3, the energy costs match.
Use a seasonal efficiency figure for a full-year comparison. A single mild-day COP is not a prediction of winter or annual performance. Read the difference between COP and SCOP before using a product specification.
Include only the fixed costs that change
You can add annual maintenance or standing charges under advanced settings. If you keep gas for cooking or hot water, switching your room heating does not necessarily remove your gas standing charge. Likewise, your existing electricity standing charge usually remains whichever heating source you choose.
The result compares running costs. It does not include the price of a heat pump, radiator upgrades, finance or grants. A lower annual bill does not by itself establish a worthwhile payback period.
Background: Energy Saving Trust: air source heat pumps. Calculation details and exclusions are in our methodology.