An air source heat pump heating a typical home costs about £760 a year to run at the price cap for 1 October to 31 December 2026. That is about the same as a gas boiler doing the same job, and £110 less than gas once you stop paying the gas standing charge. Whether your heat pump comes out cheaper depends mostly on one number: how efficiently it runs.
What a typical home pays
The sums start from the gas a typical home uses in a year, 9,500 kWh on Ofgem’s medium figure, and work out the heat that gas actually delivers: 8,075 kWh, with a boiler running at 85%. They then ask what the same heat costs from a heat pump, with electricity at 26.32p per kWh against 7.97p for gas.
Heating with gas, that home spends about £760 a year on the gas itself and £110 on the standing charge. Here is the same heat from a heat pump, at a range of efficiencies:
| Efficiency (SPF) | Heat pump, a year | Against a gas boiler | If you also cap the gas |
|---|---|---|---|
| 2.5 | £850 | £90 more | £20 less |
| 2.8 (typical) | £760 | about the same | £110 less |
| 3.2 | £660 | £100 less | £210 less |
| 3.6 | £590 | £170 less | £280 less |
The highlighted row is the median from the government’s heat pump trial. Figures are for England, Scotland and Wales, rounded to the nearest ten pounds.
Efficiency decides it
A heat pump’s efficiency is its seasonal performance factor, or SPF: the heat it delivers over a year for each unit of electricity it uses. At an SPF of 2.8, every kWh of electricity becomes 2.8 kWh of heat.
The median air source heat pump in the government-funded Electrification of Heat trial ran at 2.8. At current prices a heat pump needs an SPF of about 2.8 to match a gas boiler on fuel alone, and the typical installation sits almost exactly on that line. Per unit of heat delivered, gas through a boiler costs 9.4p and electricity through a median heat pump 9.4p.
Most of what moves the number is in the installer’s hands, not the manufacturer’s:
- Low flow temperatures. A heat pump is at its most efficient sending water round the radiators at 35 to 45°C, rather than the 60 to 70°C a gas boiler typically uses.
- Radiators big enough to heat the rooms at those lower temperatures, which sometimes means replacing a few.
- Weather compensation, which turns the flow temperature down on milder days. It should be set up at installation and left on.
- The right size of unit, worked out room by room from the heat the house loses, not matched to the size of the old boiler.
A heat loss survey that covers all four will do more for your running costs than the choice of brand. Ask for the design flow temperature in writing, and be wary of any quote that doesn’t state one.
Dropping the gas standing charge
If the heat pump replaces your only gas appliance, you can have the gas supply capped and stop paying the standing charge: £110 a year at the current price cap. That is the difference between the last two columns in the table. It only applies if nothing else in the house uses gas, so a gas hob or gas fire keeps you paying it.
Electricity is VAT-free until 31 March 2027
Household electricity in Great Britain is zero-rated for VAT until 31 March 2027, and the rates above already reflect that. After that date it goes back to 5%. On today's prices, a typical heat pump would then cost about £800 a year, which is £70 less than gas with the standing charge dropped.
Northern Ireland sits outside the price cap and kept VAT on electricity, so the figures on this page are for England, Scotland and Wales.
Tariffs change the sums
Heat pump and time-of-use tariffs can make a real difference. Some suppliers offer a lower rate to heat pump owners, and others charge less overnight, when a heat pump with a hot water cylinder can do much of its work.
We haven’t modelled them, because the rates vary by supplier and change often. The figures above use the standard price cap for both fuels, which is the fair like-for-like comparison. If you’re on one of these tariffs, or planning to switch, work the difference through with the rate you’d actually pay.
How we worked this out
- Energy prices: Ofgem, energy price cap unit rates and standing charges, for 1 October to 31 December 2026, averaged across Great Britain and paying by Direct Debit.
- How much gas a typical home uses: Ofgem typical domestic consumption values, as summarised by Energy UK, 9,500 kWh a year.
- Heat pump efficiency: Energy Systems Catapult, Electrification of Heat demonstration project. The median is measured across the whole system, backup heaters included.
- Boiler efficiency: 85%, a typical in-use figure. Condensing boilers are rated higher, but a field trial in real homes measured 82.5% on average for combi boilers (Energy Saving Trust for DECC, in-situ monitoring of efficiencies of condensing boilers).
- VAT on electricity: HMRC, temporary zero rate of VAT for domestic electricity in Great Britain.
The sums assume the heat pump takes over everything the gas used to do, hot water included. Homes vary a great deal, so treat this as a guide to the comparison, not a forecast of your bill.