How Heat Pumps and Gas Boilers Compare on Running Costs
An air source heat pump (ASHP) produces 3-4 units of heat for every unit of electricity consumed, measured as a Coefficient of Performance (COP). At current UK energy prices with electricity at 24.5p/kWh and gas at 6.4p/kWh, a well-installed heat pump costs approximately the same to run as a modern gas boiler for a well-insulated home.
Annual Running Cost Comparison
| System | Fuel Cost | Efficiency | Annual Cost (3-bed semi) | CO2 Emissions |
|---|---|---|---|---|
| Old gas boiler (15+ years) | 6.4p/kWh | 70-80% | £1,200-£1,400 | 4.2 tonnes/yr |
| New A-rated gas boiler | 6.4p/kWh | 92-94% | £850-£1,000 | 3.1 tonnes/yr |
| Air source heat pump | 24.5p/kWh | COP 3.0-3.5 | £800-£1,100 | 1.5 tonnes/yr |
| ASHP + solar panels | Mixed | COP 3.0-3.5 | £400-£700 | 0.5 tonnes/yr |
The Boiler Upgrade Scheme Explained
The UK government Boiler Upgrade Scheme (BUS) provides grants of £7,500 towards air source heat pump installation. This reduces the typical installed cost from £10,000-£14,000 to £2,500-£6,500. The scheme runs until March 2028 and is available to homeowners in England and Wales with valid EPC certificates.
Which Homes Suit Heat Pumps Best
Heat pumps perform optimally in homes with good insulation, particularly loft insulation of 270mm or more, cavity wall insulation, and double or triple glazing. Properties with an EPC rating of D or above are generally suitable without major preparatory work. Larger radiators or underfloor heating improve performance as heat pumps work most efficiently at lower flow temperatures of 35-45°C compared to 60-75°C for gas boilers.
Installation Requirements and Disruption
An ASHP installation typically takes 2-3 days. The outdoor unit requires a space of approximately 1m x 1m with good airflow, positioned at least 1m from boundaries. Indoor work involves replacing the boiler, fitting a hot water cylinder (if not already present), and potentially upgrading radiators. Noise levels for modern units are 40-45 dB at 1 metre, comparable to a refrigerator.
Future-Proofing Your Heating Investment
The UK government plans to phase out new gas boiler installations from 2035. Electricity is progressively decarbonising through renewable energy growth, meaning heat pump carbon savings will increase over time. Properties with heat pumps already show higher valuations according to estate agent reports.
