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Heat pump vs gas boiler running cost calculator
Enter your yearly gas use to see what the same heat would cost from a heat pump, and the efficiency your heat pump needs to beat gas.
Defaults from our data file, last updated 2026-10-20.
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.
How the comparison works
A gas boiler turns most of the gas it burns into heat. A modern condensing boiler manages around 85–90% in real homes. Multiply your yearly gas use by that efficiency and you get the actual heat your home uses for heating and hot water. A heat pump delivers that same heat using electricity, but it moves heat from the outside air instead of making it. Each unit of electricity typically delivers 2.5–4 units of heat. That ratio over a whole year is the Seasonal Coefficient of Performance (SCOP).
The calculator divides your heat demand by the SCOP to get the electricity the heat pump needs, prices it at your electricity rate, and compares it with what you pay for gas. If you go fully electric you can also close your gas account and stop paying the gas standing charge, worth about £108 a year at the current cap. The "break-even SCOP" shows the efficiency your heat pump must reach to match gas costs.
Default figures
- Gas use: 9,500 kWh a year, Ofgem's medium typical domestic consumption value from 1 July 2026 (it was 11,500 kWh before). Your annual statement shows your real figure. Use it if you can, but remember it includes cooking if you have a gas hob.
- Prices: 7.97p per kWh gas and 26.32p per kWh electricity, with a 29.68p daily gas standing charge. These are Ofgem price cap averages for Direct Debit customers from 1 October to 31 December 2026. Gas includes 5% VAT, and electricity carries no VAT until 31 March 2027.
- SCOP 3.0: a reasonable middle estimate for a well-installed air source heat pump. Good installations with low flow temperatures and larger radiators often achieve 3.5 or more, while poor ones can fall below 2.5.
Worked example
A home using 9,500 kWh of gas with an 88% efficient boiler needs about 8,360 kWh of heat. At a SCOP of 3.0 a heat pump uses about 2,787 kWh of electricity, which costs £733 at the cap rate. The gas costs £757, plus £108 in standing charges if you would otherwise keep the account, so £866 in total. Switching saves roughly £132 a year, or only about £24 if you keep the gas account for cooking. At a SCOP of 3.5 the saving rises to about £237. At 2.5 the heat pump costs more. Running costs are very sensitive to installation quality.
Ways to cut heat pump running costs
- Heat-pump tariffs. Tariffs like Cosy Octopus offer cheaper electricity at several points in the day. Running the heat pump harder in those windows can cut your average price well below the cap. Compare options with our tariff comparison.
- Low flow temperatures. Each degree lower generally improves efficiency. Correctly sized radiators, weather compensation and leaving the system on steadily all help.
- Add solar. Daytime solar can power the heat pump and hot water cylinder, especially in spring and autumn.
- Insulate first. Loft and cavity wall insulation reduce heat demand and let you fit a smaller, cheaper unit.
Upfront cost and grants
Running costs are only part of the picture. Air source heat pumps cost far more to install than a boiler, often £10,000–£14,000 before support. In England and Wales the Boiler Upgrade Scheme gives £7,500 off, which brings many installs close to the cost of a new boiler. Heat pumps also last around 15–20 years and need less servicing than a gas boiler, but they need space for an outdoor unit and usually a hot water cylinder.
FAQs
Is a heat pump cheaper to run than gas?
At October 2026 price cap rates, electricity costs about 3.3 times as much per kWh as gas. A heat pump needs a SCOP of around 2.9 (or about 2.5–2.6 if you also drop the gas standing charge) to break even. A well-installed system usually beats that, but the margin is modest without a heat-pump tariff.
What SCOP should I expect?
Manufacturer figures can be optimistic. Independent field trials in UK homes have found typical real-world SCOPs around 2.8–3.5, with the best installations higher.
Does a heat pump work in cold weather?
Yes. Air source heat pumps work below freezing, but efficiency falls as it gets colder. A correctly sized system is designed for your local winter conditions.
Should I include cooking gas?
If you cook on gas, subtract a few hundred kWh from your yearly gas figure for a fairer heating-only comparison.
Related calculators
Sources
- Ofgem – Energy price cap unit rates and standing charges (1 Oct–31 Dec 2026)
- Ofgem – Changes to energy price cap 1 October to 31 December 2026
- Ofgem – Review of typical domestic consumption values: decision (2026 TDCVs)
- Energy Saving Trust – Air source heat pumps
- GOV.UK – Boiler Upgrade Scheme: what you can get
- Energy Review – Octopus price change log (Oct 2026)
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.