Heat Pump Running Costs vs a Gas Boiler
A gas boiler turns most of each unit of gas into heat. A heat pump turns each unit of electricity into two to three units of heat, and electricity costs over three times as much as gas. The result depends on how efficient the heat pump is in use, the two unit prices, and whether you keep paying the gas standing charge.
Prices default to the Ofgem price cap for 1 October to 31 December 2026, GB average, Direct Debit. Use your own tariff if you know it. A heat pump tariff with cheap overnight rates changes the result.
On your annual statement. 9,500 kWh is Ofgem's typical medium household.
These three figures are the spread measured across 428 air source heat pumps in the government's Electrification of Heat trial, including hot water and the backup heater: lower quartile, median and upper quartile. 84% is SAP's winter figure for a condensing combi. Its summer figure, for hot water, is 75%, so using 84% for all the gas leans slightly against the heat pump.
How the running costs are worked out
Gas cost = heat ÷ boiler efficiency × gas price + gas standing charge
Heat pump cost = heat ÷ SCOP × electricity price (+ gas standing charge if kept)
SCOP is the heat pump's seasonal coefficient of performance: units of heat out for each unit of electricity in, averaged over a year. The electricity standing charge is paid whichever you choose, so it is left out of both sides. The gas standing charge stops only if you close the gas account.
The price of a unit of heat from gas and from a heat pump
Divide the price of a unit of each fuel by its efficiency and you get the price of a unit of heat. At the October 2026 cap, gas heat from an 84% boiler costs 7.97 ÷ 0.84 = 9.49p a kWh. Heat pump heat at a SCOP of 2.78 costs 26.32 ÷ 2.78 = 9.47p. The two are almost level. On unit prices alone, a typical heat pump at the October 2026 cap is marginally cheaper than gas, and a small change in SCOP can put it on either side.
Running costs for a house using 9,500 kWh of gas
A house using Ofgem's typical 9,500 kWh of gas a year, through an 84% condensing boiler:
- Heat and hot water: 9,500 × 0.84 = 7,980 kWh
- Gas: 9,500 × 7.97p = £757.15, plus 365 × 29.68p = £108.33 standing, total £865.48
- Heat pump at SCOP 2.78: 7,980 ÷ 2.78 = 2,870.5 kWh × 26.32p = £755.52
- With the gas disconnected: saves £109.97 a year, almost all of it the standing charge
- Keeping the gas for a hob: saves £1.63, about break-even
The same house with a better install at SCOP 3.05 saves £176.85 with the gas disconnected. A poorer one at 2.55 saves £41.82, and costs £66.51 more a year if the gas stays connected.
Electricity carries no VAT from 1 October 2026 to 31 March 2027. If VAT returns at 5% after that, the heat pump's electricity cost rises by 5%. A heat pump tariff with cheaper rates at night or at off-peak times can change the result by more than any of the above. If you have one, enter your blended rate.
For the cost of buying one, the heat pump cost calculator gives the typical installed price for your size of heat pump, and the Boiler Upgrade Scheme checker the grant that comes off it.
Where the prices and efficiency figures come from
| Input | Default | Source, read 28 September 2026 |
|---|---|---|
| Electricity unit rate | 26.32p/kWh | Ofgem price cap, 1 Oct to 31 Dec 2026, GB average Direct Debit, no VAT on electricity |
| Gas unit rate and standing charge | 7.97p/kWh, 29.68p/day | Same, including 5% VAT |
| Gas used a year | 9,500 kWh | Ofgem typical domestic consumption, medium, from 1 July 2026 |
| Boiler efficiency | 84% | SAP 10.2 Table 4b, condensing combi, gross basis as on gas bills |
| Heat pump SCOP | 2.78 | Electrification of Heat trial (Energy Systems Catapult for DESNZ, Dec 2024), median of 428 air source heat pumps, including hot water and backup heater |
Manufacturers' data sheets quote much higher figures at 35 °C water: Daikin 4.5 to 4.7 for its Altherma 3 monobloc, Vaillant up to 5.03 for the aroTHERM plus (read September 2026). In the trial the measured figure was below the design estimate in 92% of homes, by 18% on average. In the trial, heat pumps running at 35 °C water achieved a median COP of 3.50, against 2.38 at 55 °C. Use the radiator size calculator to see what size radiators a low flow temperature needs.
Heat pump and gas running cost questions
Is a heat pump cheaper to run than a gas boiler?
Only just at the October to December 2026 price cap, and mostly because of the gas standing charge. A kWh of heat from an 84% efficient boiler costs 9.49p; from a heat pump with the measured median efficiency of 2.78 it costs 9.47p. A house using 9,500 kWh of gas saves about £110 a year if it disconnects the gas, and about £2 if it keeps it. A well-designed install or a heat pump tariff increases the saving.
What SCOP should I use?
Use 2.78 if you have no better figure. It is the median measured across 428 air source heat pumps in the government's Electrification of Heat trial. The middle half of those homes fell between 2.55 and 3.05. In 92% of the trial homes the measured figure was below the SCOP the installer predicted at design stage, by 18% on average. An installer who designs for 35 to 40 °C water makes the upper end more likely.
Do I save the gas standing charge with a heat pump?
Only if you close the gas account entirely, which means no gas hob or fire either. At the October 2026 cap the gas standing charge is 29.68p a day, £108.33 a year. In the worked example that is nearly all of the saving, so decide about the hob before comparing.
How do I find my annual heat demand?
Take the gas kWh from your annual statement and multiply by your boiler's efficiency: about 84% for a condensing boiler, about 65 to 75% for an older non-condensing one. That is the heat delivered, including hot water, which is what the heat pump would have to supply. The figure also includes cooking on a gas hob, which is a small share. The calculator does this conversion when you start from your gas use.
How much more does electricity cost than gas?
Per kWh, electricity costs 3.3 times as much as gas at the October 2026 cap: 26.32p against 7.97p. Against an 84% boiler, a heat pump needs a SCOP of about 2.8 to match gas on the price of heat. If you also stop paying the gas standing charge, a typical home using 9,500 kWh of gas breaks even at a SCOP of about 2.4. Electricity carries no VAT from 1 October 2026 to 31 March 2027, which narrows the gap for now.
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