Home › Heat pumps › Heat pump vs gas boiler
Heat pump vs gas boiler: which costs less?
With the £7,500 grant, a heat pump costs about £5,000 against roughly £2,300–£2,700 for a new boiler. Whether it pays back depends almost entirely on how efficiently it runs and what tariff you're on.
Upfront cost
- Replacement gas boiler: about £2,300–£2,700 for a typical like-for-like combi swap (editorial estimate).
- Air source heat pump: our working estimate is £12,500 installed, minus the £7,500 Boiler Upgrade Scheme grant, which leaves about £5,000. Quotes vary widely, and radiator or cylinder upgrades can add cost. See the Boiler Upgrade Scheme FAQ.
Running costs at today's prices
A typical home using Ofgem's medium 9,500 kWh of gas a year, with a boiler around 88% efficient, needs about 8,360 kWh of heat. At the 1 October to 31 December 2026 cap (7.97p/kWh plus 29.68p a day standing charge), that gas costs about £865 a year. A heat pump's running cost depends on its seasonal efficiency (SCOP), which is how many units of heat it makes per unit of electricity:
| SCOP | Electricity used | Heat pump cost (at 26.32p) | Gas cost (incl. standing charge) | Yearly saving | 15-year position vs new boiler* |
|---|---|---|---|---|---|
| 2.5 | 3,344 kWh | £880 | £865 | −£15 | −£2,720 |
| 3.0 | 2,787 kWh | £733 | £865 | +£132 | −£520 |
| 3.5 | 2,389 kWh | £629 | £865 | +£237 | +£1,052 |
| 4.0 | 2,090 kWh | £550 | £865 | +£315 | +£2,231 |
*15-year position = yearly saving × 15, minus the extra upfront cost of the heat pump after the grant (£5,000) over a mid-range boiler (£2,500). Assumes you drop gas completely, so the standing charge is saved. Constant prices, no maintenance differences. Indicative only.
Tariffs change the picture
The table uses the flat price cap electricity rate. Heat pump tariffs such as Cosy Octopus offer cheaper slots. If around 60% of your heat pump's use falls in the cheaper periods, the blended rate is about 24.4p/kWh, which cuts heat pump running costs a lot. Solar panels help too, mostly in spring and autumn. Run your own figures in the heat pump running cost calculator and compare tariffs in our smart tariff comparison.
Other things to weigh
- Efficiency is in the installer's hands. Good design, with correct sizing, low flow temperatures and suitable radiators, is what gets a SCOP of 3.5 or more. Ask installers what SCOP they're designing for. Our size estimator gives a ballpark kW.
- Lifespan. Heat pumps typically last 15–20 years, and boilers 10–15.
- Hot water. Most heat pumps need a hot water cylinder, which combi-boiler homes don't have. That takes up space.
- Carbon. A heat pump on today's grid produces far less CO₂ than a gas boiler.
- Grant timing. The installer must apply first, so don't commit to a boiler swap in a rush if you're weighing up a heat pump.
FAQs
Is a heat pump cheaper to run than a gas boiler?
It depends on efficiency and tariff. At the current cap (26.32p electricity, 7.97p gas), a heat pump with a SCOP of about 3 or above, in a home that drops gas entirely, usually costs less to run. On a heat pump tariff the margin is bigger.
How much does a heat pump cost compared with a boiler?
Roughly £5,000 for an air source heat pump after the £7,500 grant, against about £2,300–£2,700 for a replacement gas boiler, though quotes vary widely.
What SCOP should I expect?
Well-designed UK installations commonly achieve a SCOP of about 3 to 4. Poor design, high flow temperatures and undersized radiators can push it below 2.5.
Do I need to replace my radiators?
Sometimes. Heat pumps run at lower flow temperatures, so a few rooms may need larger radiators. A proper heat loss survey will say which ones.
Related calculators
Heat pump running cost calculator
Boiler Upgrade Scheme FAQ
Boiler Upgrade Scheme checker
Standing charges explained
Sources
- Ofgem – Typical domestic consumption values (2026)
- Ofgem – Energy price cap unit rates and standing charges (1 Oct–31 Dec 2026)
- GOV.UK – Boiler Upgrade Scheme: what you can get
- Heatable – New boiler installation costs 2026
- Energy Saving Trust – Air source heat pumps
- Energy Review – Octopus price change log (Oct 2026)
- HMRC – VAT on energy-saving materials and heating equipment (Notice 708/6)
Estimates only, not financial advice. Results use average UK figures and the assumptions shown. Your real costs depend on your home, tariff, region and installer quotes. Always get several quotes from certified installers and check current tariff rates before deciding. Don't rely on these results alone: see our disclaimer.