Free UK running-cost comparison · reviewed 2 October 2026
Heat pump vs gas boiler cost calculator.
See annual running costs, a monthly average and the SPF needed to beat gas. Use your own tariffs and heat demand; installation costs are a separate, optional comparison. No email or postcode required.
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Example running-cost comparisonLive calculation · no contact details needed.
ResultHeat-pump electricity cost
£1,052.80 / yearAbout 4,000 kWh electricity for 12,000 kWh useful heat at SPF 3.Annual running costs: heat pump £1,052.80; boiler £1,062.67. Entered servicing is £0 / £0 respectively. Gas standing charge is excluded because the connection stays. Electricity standing charge is excluded from both options.
Compare installation and total costs 10 years
10-year cost result
Gas boiler£1,401 lower over the selected periodWhat can change this estimate? Assumptions
What can flip the result
- At the entered unit rates, the heat pump needs a seasonal performance factor above 2.97 to beat the boiler on energy alone.
- Gas standing charge is excluded because the gas connection is retained or used for another appliance.
- A time-of-use heat-pump tariff can change the effective electricity rate; use the weighted rate you realistically expect to pay.
- Hot-water demand, controls, flow temperature, weather and actual system performance can move both annual totals.
Calculation boundaries
- Annual heat demand is useful heat delivered to the home, not the fuel use shown on a bill.
- The monthly energy figure is annual cost divided by 12, not a prediction of each month's bill; winter heating use will differ.
- Electricity standing charge is excluded from both options because the home still needs an electricity connection.
- Energy prices, maintenance figures and system performance are held constant in today's money for the selected period.
- Finance interest, repair risk, equipment replacement, inflation, export income and property-value effects are excluded.
- The result is a scenario comparison, not a guarantee of bills, savings or payback.
Scenario, not a savings promise
Compare complete written scopes and ask for a room-by-room heat-loss calculation, design flow temperature and seasonal performance estimate. Enter the rates from your own bills before making a decision.
After your free estimate
Want an exact local price?
A heat-loss calculation, system design and written scope are needed to price the equipment, emitters, cylinder, electrics and commissioning.
Optional. Your estimate stays visible. We'll use a short qualification step so unsuitable or out-of-area requests are not passed around.
How the calculation works
Compare useful heat, not mismatched meter readings.
The heat-pump side divides annual useful heat demand by seasonal performance factor, then applies the electricity rate. The boiler side divides the same heat demand by seasonal efficiency and applies the gas rate. The monthly average is annual energy cost divided by 12, not a prediction of each month's bill. Entered maintenance and any genuinely avoidable gas standing charge are shown separately from energy.
The starting tariffs are Ofgem's Great Britain Direct Debit averages for 1 October–31 December 2026, with gas VAT included and no electricity VAT in that period. Regional rates, payment methods and fixed or time-of-use tariffs can differ. Use the final unit prices from your bill; the tool does not add VAT again.
For the optional installation comparison, annual costs are held constant and added to complete upfront project costs. Simple payback is not a forecast of tariffs or system lifetime; it may fall beyond the comparison period. Use complete written quotes and confirm any support eligibility separately.
What changes the result
Factors worth checking before you decide.
Your property's useful space-heating and hot-water demand.
The installed heat pump's whole-system seasonal performance.
Boiler seasonal efficiency under real operating conditions.
Actual electricity and gas tariffs, including time-of-use weighting.
Whether the gas connection and standing charge can really be removed.
Complete installation scope, maintenance, finance and replacement timing.
Worked examples
See how the assumptions move the answer.
At 26.32p/kWh, 4,000 kWh of heat-pump electricity costs £87.73 as a monthly average. This excludes servicing and installation.
Raising whole-system SPF to 4 reduces this example's electricity use to 3,000 kWh. Use an installer-supported seasonal estimate, not a best-case laboratory COP.
The boiler uses about 13,333 kWh of gas at 7.97p/kWh. The energy-only break-even heat-pump SPF is 2.97; maintenance and gas-connection choices can change the full comparison.
Common questions
Questions homeowners ask before spending.
Is a heat pump cheaper to run than a gas boiler?
It depends on your tariffs, seasonal performance and boiler efficiency. With 12,000 kWh of useful heat, SPF 3 and 90% boiler efficiency, the 1 October–31 December 2026 starting rates give £1,052.80 of heat-pump electricity versus £1,062.67 of boiler gas per year. These are energy-only examples, not household bills or guaranteed savings.
What SPF does a heat pump need to beat a gas boiler?
The energy-only break-even SPF is electricity rate × boiler efficiency ÷ gas rate. With the initial 26.32p electricity, 7.97p gas and 90% boiler efficiency, the threshold is about 2.97. Maintenance and any genuinely avoidable gas standing charge are separate.
How much does a heat pump cost to run per month?
The starting example uses 4,000 kWh of electricity a year at 26.32p/kWh: £1,052.80 per year, or £87.73 as a monthly average. That is annual cost divided by 12, not a flat monthly bill: winter use will be higher than summer use. Enter your home's heat demand, expected SPF and tariff for your own scenario.
Where should annual heat demand come from?
Ask for an annual useful-heating-demand estimate based on the property's heat-loss calculation. An EPC estimate can be a starting point. Do not copy annual gas consumption directly because boiler losses, hot water, cooking and weather can make it different from useful heat delivered.
Does the calculation include the gas standing charge?
Only when you say the gas connection could be removed completely. If gas remains for cooking, a fire or another appliance, the standing charge is excluded from the heating comparison.
Is this a payback guarantee?
No. The model holds entered prices and performance constant in today's money. It excludes finance, inflation, repairs, replacement and property-value effects, so its payback is a simple scenario rather than a forecast.
Sources and review trail
Transparent inputs, versioned model.
- Last reviewed
- 2 October 2026
- Model/version
- uk-heat-pump-vs-boiler-2026.10.1
- Ofgem: Great Britain Direct Debit price-cap averages, 1 October–31 December 2026 ↗
- Energy Saving Trust: air-source heat-pump installation and running-cost factors ↗
- Energy Saving Trust: gas-boiler cost, system choices and installer requirements ↗
- Ofgem: Seasonal Performance Factor definition and system-performance boundary ↗