8 kW Air Source Heat Pump running cost — Cold winter day (12 h)
A 8 kW Air Source Heat Pump (COP 2.7, BEIS data) draws 2.96 kW of electricity per hour. Running 12 hours/day uses 35.6 kWh and costs £9.28/day at the Ofgem cap of 26.11p/kWh (1 July to 30 September 2026).
8 kW Air Source Heat Pump — Cold winter day (12 h): 8 kW ÷ COP 2.7 = 2.96 kW electricity draw × 12 h = 35.6 kWh/day = £9.28/day. Weekly: £64.98. Annual: £3388.50. Context: UK winter (Dec–Feb), outdoor temp < 5°C. Source: DESNZ/BEIS (OGL v3.0) + Ofgem.
- Per day
- £9.28
- Per week
- £64.98
- Per month
- £282.37
- Per year
- £3388.50
System specification
- Heat output
- 8 kW
- Type
- Air-source (ASHP)
- Seasonal COP
- 2.7
- Electricity draw
- 2.96 kW/h
- Daily kWh
- 35.6 kWh
- Scenario
- 12 h/day
BEIS Heat Pump Information Note 2024 — 8 kW ASHP, typical SCOP 2.7 for UK climate
How the cost is worked out
- Electricity draw per hour: 8 kW ÷ COP 2.7 = 2.96 kW.
- Daily kWh: 2.96 kW × 12 h = 35.6 kWh.
- Daily cost: 35.6 kWh × 26.11p/kWh = £9.28.
- Weekly: £9.28 × 7 = £64.98.
- Annual: £9.28 × 365 = £3388.50.
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COP 2.7 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).