Comparisons
Air source heat pump vs gas boiler: which is cheaper to run?
Last updated 2026-08-18
The question everyone asks: "If electricity costs more than gas per kWh, how can a heat pump possibly save me money?"
The answer is efficiency. A gas boiler converts 90p of every £1 of gas into heat (the rest goes out the flue). A heat pump converts £3–£4 of heat for every £1 of electricity it uses. That 3:1 ratio — called the Coefficient of Performance (COP) — is why heat pumps win on running costs for most homes.
Running costs compared
| Factor | Gas boiler | Air source heat pump |
|---|---|---|
| Fuel cost per kWh (2026) | ~7.4p | ~27p |
| Efficiency | ~90% | 300% (COP 3.0) |
| Effective cost per kWh of heat | ~8.2p | ~9.0p |
| Annual heating cost (typical 3-bed) | ~£840 | ~£920 |
| Annual standing charge | ~£115 | £0 (if no gas needed) |
| True annual cost | ~£955 | ~£920 |
As you can see, the running costs are close — and for many homes the heat pump is already cheaper when you factor in the gas standing charge. The real savings come when you're replacing oil or LPG heating, or when electricity prices drop relative to gas (which the government's "green gas" policies are designed to do).
What about installation costs?
- New gas boiler: £2,000–£3,500 (no grant available)
- Air source heat pump: £8,000–£14,000, minus £7,500 grant = £500–£6,500
So the heat pump is cheaper to install than you might think — and when you factor in that a new gas boiler will need replacing again in 10–15 years (another £2,000–£3,500), the lifetime cost of a heat pump (which lasts 15–20 years) starts to look very competitive.
When a heat pump saves you money
- Replacing oil or LPG — oil and LPG are significantly more expensive than mains gas, so heat pumps save money from day one.
- Well-insulated homes — lower heat demand means a smaller, cheaper heat pump and lower running costs.
- Homes with solar panels — if you generate your own electricity, the running cost of a heat pump drops dramatically.
- Homes with underfloor heating — underfloor heating works at lower temperatures (perfect for heat pumps), improving efficiency.
When a gas boiler might still make sense
- Poorly insulated homes — if your home loses heat fast, a heat pump may struggle to keep up efficiently without insulation upgrades.
- Very tight budgets — even with the grant, the upfront cost of a heat pump is more than a boiler replacement (though the grant narrows this gap significantly).
- Small properties — for a small flat with low heating demand, the savings might not justify the installation cost.
The bottom line
For most UK homes replacing gas, the heat pump costs roughly the same to run as a gas boiler — but you get £7,500 off the installation, lower carbon emissions, and you're insulated from future gas price hikes. For homes replacing oil or LPG, the heat pump is cheaper to run from day one.
The best way to know for your specific home is to get quotes from MCS-certified installers. They'll assess your property, estimate running costs, and tell you whether you'd benefit from insulation upgrades first.
Want to see if a heat pump makes sense for your home? Check your grant eligibility and get free quotes from local installers — it takes under 2 minutes.
Check what you could get in under 2 minutes
Answer a few quick questions and we'll tell you which UK grants you're likely to qualify for — then get free quotes from vetted installers in your area.