12 kW Air Source Heat Pump running cost — Spring/autumn shoulder season (5 h)
A 12 kW Air Source Heat Pump (COP 2.5, BEIS data) draws 4.80 kW of electricity per hour. Running 5 hours/day uses 24.0 kWh and costs £6.27/day at the Ofgem cap of 26.11p/kWh (1 July to 30 September 2026).
12 kW Air Source Heat Pump — Spring/autumn shoulder season (5 h): 12 kW ÷ COP 2.5 = 4.80 kW electricity draw × 5 h = 24.0 kWh/day = £6.27/day. Weekly: £43.86. Annual: £2287.24. Context: UK spring/autumn (Mar–May, Sep–Nov). Source: DESNZ/BEIS (OGL v3.0) + Ofgem.
- Per day
- £6.27
- Per week
- £43.86
- Per month
- £190.60
- Per year
- £2287.24
System specification
- Heat output
- 12 kW
- Type
- Air-source (ASHP)
- Seasonal COP
- 2.5
- Electricity draw
- 4.80 kW/h
- Daily kWh
- 24.0 kWh
- Scenario
- 5 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 × 5 h = 24.0 kWh.
- Daily cost: 24.0 kWh × 26.11p/kWh = £6.27.
- Weekly: £6.27 × 7 = £43.86.
- Annual: £6.27 × 365 = £2287.24.
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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).