Heat Pump Running Cost Calculator
Calculate estimated annual electricity costs for an air source heat pump in the UK. Adjust the inputs below to match your home and electricity tariff.
Your Details
Typical annual heat demand: 12,000 kWh
SCOP measures how many units of heat you get per unit of electricity. Higher is better.
Check your energy bill. UK average is ~28p/kWh (2025). Octopus Cosy tariff is lower overnight.
How it works
This calculator estimates the electricity cost of running an air source heat pump for space heating and hot water in a UK home. It uses your home size to estimate annual heat demand, then divides by the SCOP (seasonal coefficient of performance) to find electricity consumption.
The formula: Electricity (kWh) = Heat demand (kWh) ÷ SCOP. Then multiply by your unit rate. Real costs vary by insulation quality, thermostat settings, and weather.
Typical UK heat demand by home size
| Home size | Annual heat demand | Notes |
|---|---|---|
| Small (1-2 bed flat) | 8,000 kWh/year | Well-insulated modern flat |
| Medium (2-3 bed house) | 12,000 kWh/year | Semi-detached, average insulation |
| Large (4+ bed house) | 18,000 kWh/year | Detached, older build |