12 kW Air Source Heat Pump running cost — Mild winter day (8 h)
A 12 kW Air Source Heat Pump (COP 2.5, BEIS data) draws 4.80 kW of electricity per hour. Running 8 hours/day uses 38.4 kWh and costs £10.03/day at the Ofgem cap of 26.11p/kWh (1 July to 30 September 2026).
12 kW Air Source Heat Pump — Mild winter day (8 h): 12 kW ÷ COP 2.5 = 4.80 kW electricity draw × 8 h = 38.4 kWh/day = £10.03/day. Weekly: £70.18. Annual: £3659.58. Context: UK winter (Nov–Mar), outdoor temp 5–10°C. Source: DESNZ/BEIS (OGL v3.0) + Ofgem.
- Per day
- £10.03
- Per week
- £70.18
- Per month
- £304.96
- Per year
- £3659.58
System specification
- Heat output
- 12 kW
- Type
- Air-source (ASHP)
- Seasonal COP
- 2.5
- Electricity draw
- 4.80 kW/h
- Daily kWh
- 38.4 kWh
- Scenario
- 8 h/day
BEIS Heat Pump Information Note 2024 — 12 kW ASHP, conservative SCOP 2.5 for larger homes
How the cost is worked out
- Electricity draw per hour: 12 kW ÷ COP 2.5 = 4.80 kW.
- Daily kWh: 4.80 kW × 8 h = 38.4 kWh.
- Daily cost: 38.4 kWh × 26.11p/kWh = £10.03.
- Weekly: £10.03 × 7 = £70.18.
- Annual: £10.03 × 365 = £3659.58.
Get a heat pump installation quote
A MCS-certified heat pump installer can assess your home and give you a detailed cost and savings estimate. GeraHome connects you with qualified HVAC engineers.
Find a heat pump installerSame scenario — other systems
Track heat pump running costs
Updated each time the Ofgem cap changes. No spam.
No spam. Unsubscribe anytime. A Gera Services product.
COP 2.5 from DESNZ/BEIS — Heat Pump Information Note: Seasonal Performance Data 2024 (OGL v3.0). Unit rate 26.11p/kWh from Ofgem — Energy price cap unit rates and standing charges (1 July to 30 September 2026).