Heat pump vs gas boiler: what it really costs
For a typical 3-bedroom semi (about 12,000 kWh/yr), an air source heat pump (SCOP 3.5) costs about £895/yr to run versus about £1,083/yr for mains gas. That is about £188 saved a year. Use the calculator to put in your own home and tariff.
Your standard rate. The tariff scenario is shown separately.
Efficiency. 3.5 is typical.
On a standard tariff (price cap)
electricity at 26.11p/kWh
£188 /yr saved
Heat pump £895/yr · payback 19.9 yrs
On a heat pump tariff (~15p/kWh)
cheap-rate electricity
£569 /yr saved
Heat pump £514/yr · payback 6.6 yrs
Heat pump tariffs (Octopus Cosy, EDF, Scottish Power) offered off-peak rates of about 14p to 15p/kWh in June 2026. The ~15p scenario assumes most heating runs in the cheap hours.
- Now: mains gas heating
- £1,083/yr
- Gas standing charge saved
- £106/yr
- Indicative system size
- ~6kW
- Install after grant
- £3,750
- CO₂ saved
- 1,730 kg/yr
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Estimate only. Real figures depend on your home, install and tariff. Prices: Ofgem cap, Jul-Sep 2026.