8 kW Ground Source Heat Pump running cost — Always-on low-modulating (6 h equivalent)
A 8 kW Ground Source Heat Pump (COP 3.5, BEIS data) draws 2.29 kW of electricity per hour. Running 6 hours/day uses 13.7 kWh and costs £3.58/day at the Ofgem cap of 26.11p/kWh (1 July to 30 September 2026).
8 kW Ground Source Heat Pump — Always-on low-modulating (6 h equivalent): 8 kW ÷ COP 3.5 = 2.29 kW electricity draw × 6 h = 13.7 kWh/day = £3.58/day. Weekly: £25.07. Annual: £1306.99. Context: Inverter heat pump in modulating mode, UK average. Source: DESNZ/BEIS (OGL v3.0) + Ofgem.
- Per day
- £3.58
- Per week
- £25.07
- Per month
- £108.92
- Per year
- £1306.99
System specification
- Heat output
- 8 kW
- Type
- Ground-source (GSHP)
- Seasonal COP
- 3.5
- Electricity draw
- 2.29 kW/h
- Daily kWh
- 13.7 kWh
- Scenario
- 6 h/day
BEIS Heat Pump Information Note 2024 — 8 kW GSHP, typical SCOP 3.5
How the cost is worked out
- Electricity draw per hour: 8 kW ÷ COP 3.5 = 2.29 kW.
- Daily kWh: 2.29 kW × 6 h = 13.7 kWh.
- Daily cost: 13.7 kWh × 26.11p/kWh = £3.58.
- Weekly: £3.58 × 7 = £25.07.
- Annual: £3.58 × 365 = £1306.99.
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COP 3.5 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).