Heat pump vs gas or oil boiler: running cost calculator
Would a heat pump be cheaper to run than your gas or oil boiler? Compare your heating costs now with an air source heat pump, including the Boiler Upgrade Scheme grant, and see if the extra upfront cost pays back. Results update as you type.
Your inputs
Oil or LPG homes off the gas grid may get an extra £1,500 grant until March 2027
Default: 9,500 kWh of gas (Ofgem typical medium use from 1 July 2026) × 85% boiler efficiency, rounded. Better: last year's gas kWh × your boiler efficiency.
Our assumption for a modern condensing boiler in real use. 50–100%
Median measured in UK homes in the Electrification of Heat trial (Energy Systems Catapult). Minimum 1
Cap average. A heat pump time-of-use tariff can be lower.
Ofgem cap average Oct–Dec 2026, incl. 5% VAT (7.59p without VAT)
Ofgem cap average Oct–Dec 2026, incl. 5% VAT (28.27p without VAT)
BoilerJuice England regional averages, October 2026 (112–114p). BoilerJuice does not state whether these averages include the 5% VAT on domestic oil
Bulk LPG, SAP/RdSAP fuel prices from July 2026 (BRE for DESNZ). £71/year standing charge not included. Used only for LPG
Kerosene, approximate
Energy Saving Trust typical cost
England and Wales. Set to 0 in Scotland or Northern Ireland.
Until March 2027, homes with no mains gas connection (GOV.UK)
Our placeholder: enter your quote. 0 if your boiler is not due for replacement.
Result
Adjust inputs to calculate
Breakdown
Cumulative net position over 15 years
Starts at minus the extra upfront cost (heat pump after grant, minus what a new boiler would cost), then adds the yearly running-cost saving.
What your result means: if it says the heat pump saves money a year, it's cheaper to run than your boiler on these numbers; if it says it costs more, your boiler is cheaper. The efficiency figure (SCOP) and your electricity rate matter most, so try a cheaper heat-pump tariff and a realistic SCOP before deciding.
Estimates for information only, not financial advice. Prices, grants and rates change, so check them with the supplier or installer before you decide. Get at least three quotes from MCS-certified installers. See our terms.
How we calculate
- Current heating cost: heat needed ÷ boiler efficiency = fuel used. Gas: kWh × unit price, plus the gas standing charge if you would disconnect. Oil: kWh ÷ kWh per litre × price per litre. LPG: kWh × price per kWh. Payback is shown only when the yearly saving is above zero.
- Heat pump cost: heat needed ÷ SCOP = electricity used × your electricity price. The electricity standing charge is paid either way, so it is left out.
- Upfront: heat pump cost − Boiler Upgrade Scheme grant (+£1,500 for off-gas oil/LPG homes until March 2027) − the cost of the boiler you would otherwise buy.
- Break-even electricity price: the electricity price at which the heat pump costs the same to run as your current system.
- Prices are held flat. Radiator upgrades, hot-water cylinder, servicing and financing are not modelled separately; include them in the installed cost if your quote does.
Sources and last updated
All figures checked on 27 October 2026 unless stated. Every default can be changed.
| Figure | Default | Source (date) |
|---|---|---|
| Gas and electricity prices | Gas 7.97p, 29.68p/day incl. 5% VAT (7.59p, 28.27p/day without VAT); electricity 26.32p | Ofgem price cap, 1 Oct–31 Dec 2026, published 26 Aug 2026 |
| Boiler Upgrade Scheme | £7,500 (+£1,500 oil/LPG to Mar 2027) | GOV.UK: Boiler Upgrade Scheme, what you can get |
| Heat pump cost | £12,000 | Energy Saving Trust: Air source heat pumps |
| Heating oil | 113p/litre | BoilerJuice regional heating-oil averages: October 2026 averages South East 113.68p, Midlands 113.52p, North West 112.46p, East Anglia 112.24p; Scotland 124.78p. Whether these include 5% VAT is not stated on the page (checked 27 Oct 2026). |
| LPG (bulk) | 9.60p/kWh | BRE: Prices used by SAP/RdSAP for calculation of fuel costs, from July 2026 (bulk LPG 9.60p/kWh, standing charge £71/year not included; bottled LPG 12.01p/kWh). Checked 27 Oct 2026. |
| SCOP 2.8 | 2.8 | Energy Systems Catapult, Electrification of Heat demonstration (DESNZ-funded): median measured air source seasonal performance factor (SPF H4) 2.80; the final reports give an average of about 2.81. Checked 27 Oct 2026. |
| Typical gas use | 9,500 kWh (heat 8,100 kWh at 85%) | Ofgem typical domestic consumption values, medium gas user, in use from 1 July 2026 (was 11,500 kWh). Checked 27 Oct 2026. |
| Boiler efficiency 85%, oil 10.35 kWh/l, new boiler £3,000 | — | Our assumptions; change them. |
Frequently asked questions
Is a heat pump cheaper to run than a gas boiler?
At the October–December 2026 cap prices it is close. Electricity (26.32p) is 3.3 times the price of gas (7.97p including 5% VAT; 7.59p without VAT), so with a SCOP of 2.8 the heat pump costs slightly more per unit of heat than an 85%-efficient boiler. It comes out ahead if you disconnect the gas and save the £108 standing charge, achieve a higher SCOP, or use a cheaper heat pump tariff. The Energy Saving Trust says the same: on standard tariffs a heat pump can cost slightly more to run, while time-of-use tariffs can make it cheaper.
How much is the Boiler Upgrade Scheme grant?
£7,500 towards an air source or ground source heat pump in England and Wales. Until March 2027 there is an extra £1,500 if your home is heated by oil or LPG and has no mains gas connection. Hybrid systems are not eligible (GOV.UK, checked 27 Oct 2026).
What about oil heating?
At about 113p a litre in October 2026, oil heat costs roughly 12.8p per kWh of heat at 85% efficiency. A heat pump at 26.32p with SCOP 2.8 costs about 9.4p, so switching from oil usually saves money.
What SCOP should I use?
Ask your installer for the design SCOP at your flow temperature. Lower flow temperatures (bigger radiators, better insulation) give higher SCOP. We use 2.8, the median measured in UK homes in the government-funded Electrification of Heat trial.
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