Heat Pump vs Gas Boiler Running Costs
Summary
At 2026 UK energy prices (28p/kWh electricity, 6p/kWh gas), a heat pump with SCOP 3.5 costs roughly the same to run as a gas boiler (90% efficient). Heat pumps become cheaper if you use a time-of-use tariff or if gas prices rise further.
The numbers (medium 3-bed house, 12,000 kWh/year heat demand)
| System | Efficiency | Energy used | Annual cost |
|---|---|---|---|
| Gas boiler | 90% efficient | 13,333 kWh gas | £800/year (at 6p/kWh) |
| Heat pump (SCOP 3.0) | 300% efficient | 4,000 kWh electricity | £1,120/year (at 28p/kWh) |
| Heat pump (SCOP 3.5) | 350% efficient | 3,429 kWh electricity | £960/year (at 28p/kWh) |
| Heat pump (SCOP 4.0) | 400% efficient | 3,000 kWh electricity | £840/year (at 28p/kWh) |
Why the difference matters
The electricity-to-gas price ratio determines the crossover point. In 2026, electricity costs ~4.7× gas per kWh. A heat pump needs SCOP >4.7× boiler efficiency to break even. Since boilers are ~90% efficient and heat pumps typically achieve SCOP 3.0-3.5, gas is currently cheaper per kWh of delivered heat in most homes.
However, this ignores carbon costs. Heat pumps emit ~40% less CO2 than gas boilers when using UK grid electricity (which is ~50% renewable as of 2026). If carbon pricing or gas price rises continue, the economics shift further towards heat pumps.
When heat pumps win on cost
- High SCOP systems (3.5+): Well-designed installations in insulated homes.
- Time-of-use tariffs: Off-peak electricity at 12-14p/kWh makes heat pumps cheaper.
- Gas price spikes: 2022-23 saw gas at 10p+/kWh, swinging economics heavily.
- No gas connection: If you use oil or LPG heating, heat pumps are usually cheaper.
Installation cost difference
A gas boiler costs £2,000-3,500 installed. An air source heat pump costs £8,000-14,000. The UK Boiler Upgrade Scheme offers £7,500 grants (as of 2026), narrowing the gap. Payback depends on lifespan (heat pumps last 15-20 years, boilers 10-15) and future energy price ratios.
Sources
- Ofgem, Energy price cap (April-June 2026)
- UK Department for Energy Security & Net Zero, Boiler Upgrade Scheme, 2024
- Energy Saving Trust, Heat pump running costs vs gas boilers, 2025
Compare for your home: Run the heat pump cost calculator with your actual energy rates.