Heat Pump vs Gas Boiler Running Costs UK 2026
At standard tariff rates, gas costs 7.51p per kWh of useful heat vs 8.17p for a heat pump — a 9% difference. Switch to an off-peak tariff and the heat pump drops to 6.00p, making it 20% cheaper than gas.
Both sides of this debate make misleading claims. This guide gives you a straight, numbers-based comparison using current Ofgem prices.
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The Numbers You Need
Gas cost per kWh heat
7.51p
6.76p ÷ 0.90 efficiency
HP cost per kWh heat
8.17p
24.5p ÷ 3.0 COP
HP cost (TOU tariff)
6.00p
18p ÷ 3.0 COP
Ofgem Q1 2026 rates. Modern condensing boiler at 90%. Air source COP 3.0.
Annual Cost Comparison by Property Size
| Property (Heat Demand) | Gas Boiler | HP Standard | Difference |
|---|---|---|---|
| Small flat (6,000 kWh) | £451 | £490 | HP £39 more |
| 3-bed semi (12,000 kWh) | £901 | £980 | HP £79 more |
| 4-bed detached (20,000 kWh) | £1,502 | £1,633 | HP £131 more |
| 5-bed detached (30,000 kWh) | £2,253 | £2,450 | HP £197 more |
Standard electricity tariff. COP 3.0. See how TOU tariffs reverse this below.
Why These Numbers Are Not the Full Story
Factor 1: Time-of-Use Tariffs
At a blended 18p/kWh: heat pump drops to 6.00p per kWh of heat — 20% cheaper than gas. For the 3-bed semi, annual cost becomes £720, saving £181/year vs gas.
Factor 2: COP Variation
At COP 3.5 on standard tariff: 7.00p per kWh — marginally cheaper than gas even without a special tariff. Read more about running cost factors.
Factor 3: Boiler Efficiency Decline
After 10 years at 85%: 7.95p/kWh. After 15 years at 80%: 8.45p/kWh. Heat pump efficiency stays stable over its 20-year life.
Factor 4: Energy Price Trends
Policy direction: gas will become relatively more expensive as carbon pricing increases. The full comparison guide explores this in depth.
Factor 5: Standing Charges
Disconnecting from gas saves £128/year in standing charges.
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Total Cost of Ownership: 20 Years
3-Bed Semi — 20-Year Total (12,000 kWh/yr)
Gas boiler (incl. replacement yr 13)
£30,080
HP standard tariff (after grant)
£27,100
Saves £2,980
HP TOU tariff (after grant)
£21,900
Saves £8,180
Gas total includes boiler replacement, running costs, servicing, and standing charges. HP includes installation (after BUS grant), running costs, and servicing.
Even in the least favourable scenario, the heat pump works out cheaper over 20 years. For payback period calculations, see our dedicated guide.
When Gas Is Genuinely Cheaper
- Standard tariff and cannot switch to TOU
- COP below 2.8 due to poor installation or high flow temperatures
- Very poorly insulated property requiring high flow temperatures
- Relatively new, efficient boiler with many years of life remaining
When the Heat Pump Is Clearly Cheaper
- Time-of-use electricity tariff
- COP 3.2+ (good installation, well-insulated home)
- Old, inefficient gas boiler
- Solar panels generating some heat pump electricity — see our solar energy guide
What We Recommend
Do not make this decision on running costs alone. The differences are small — typically £50–£200/year. Consider the total picture: the BUS grant makes installation comparable to a new boiler for many homes, heat pumps last 20+ years, energy prices will shift in the heat pump’s favour, and a heat pump adds value to your property. Use our cost calculator and suitability checker for a personalised assessment.
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Frequently Asked Questions
Are heat pumps more expensive to run than gas boilers?
At standard tariff and COP 3.0, approximately 5–10% more per kWh of heat. On a TOU tariff or COP above 3.2, the heat pump can be cheaper.
What COP do I need for a heat pump to be cheaper than gas?
COP 3.27+ on standard tariff. COP 2.4+ on a TOU tariff.
Will the government make electricity cheaper for heat pump owners?
The policy direction favours this, but no specific date has been set.
Should I wait for cheaper electricity?
If your boiler needs replacing, acting now secures the BUS grant. The running cost difference at current prices is small.
Do these figures include hot water?
Yes. Hot water accounts for 15–25% of total heat demand.
How do maintenance costs compare?
Gas: £80–£120/year servicing. Heat pump: £100–£200/year. See our maintenance guide.
About Heat Pump vs Gas Boiler Costs
The cost comparison between heat pumps and gas boilers depends on electricity tariff, seasonal COP, and the full ownership period. At 2026 prices, a heat pump on a TOU tariff is the cheapest heating option. This guide is part of our resource hub covering costs, boiler comparisons, running costs, and grants. For reducing electricity costs with solar, visit Home Solar Guide.