Heat pump running cost for a 4-bedroom semi-detached
A 4-bedroom semi-detached uses roughly 16,000 kWh of heat a year. At the current Ofgem price cap an air source heat pump (SCOP 3.5) would cost about £1,194/yr to run, versus about £1,409/yr for mains gas. That is roughly £216 saved a year. A typical ~8kW system costs about £12,500, or £5,000 after the £7,500 grant, paying back in about 23.2 years.
Your region (sets local prices)
Property type
Bedrooms
Insulation
Current heating & its price
p/kWh
p/kWh
A heat-pump tariff can be ~13-15p.
Efficiency. 3.5 is typical.
£
A heat pump would cut your heating bill by
£216/yr
15% cheaper to run · ~8kW system
- Now: mains gas heating
- £1,409/yr
- Heat pump running cost
- £1,194/yr
- Gas standing charge saved
- £106/yr
- Install after grant
- £5,000
- Payback time
- 23.2 years
- CO₂ saved
- 2,307 kg/yr
Estimate only. Real figures depend on your home, install and tariff. Prices: Ofgem cap, Jul-Sep 2026.