Heat pump electricity and cost calculator

Start with useful heat demand, not electricity or gas consumption taken unchanged from a bill. Enter a seasonal performance estimate appropriate to the installation. You can include a gas alternative when its energy price, efficiency and relevant fixed charges are known.

Formula

Heat pump electricity = annual useful heat demand ÷ SCOP. Running cost = electricity × unit price. Direct electric heating is modelled at one unit of heat per unit of electricity. Gas cost = heat demand ÷ boiler efficiency × gas unit price + entered fixed charges.

Worked example

A home needing 12,000 kWh of useful heat with a SCOP of 3 requires an estimated 4,000 kWh of heat pump electricity annually. A SCOP of 4 reduces that estimate to 3,000 kWh.

What the result means

Positive savings mean lower modelled energy costs against the selected alternative. For a replacement decision, enter the additional investment to be recovered rather than an unrelated project total.

Electricity price · United Kingdom

£0.2611/kWh is Ofgem’s average capped electricity unit rate for standard variable tariffs paid by Direct Debit in England, Scotland and Wales, valid from 1 July to 30 September 2026. It includes 5% VAT and excludes the separate standing charge. It is not an average across all contracts and does not apply to Northern Ireland. Use your own tariff where available.

Last reviewed: 9 September 2026 · Ofgem · July–September 2026

Enter the unit rate including any applicable tax. Check your bill rather than adding a tax percentage automatically. Standing charges, export payments and subscription fees are separate. Ofgem information applies to Great Britain; Northern Ireland has its own regulator and market arrangements.

Assumptions and limits

Weather, insulation, flow temperature, hot water, defrosting and backup heating influence real performance. Maintenance, grants, finance and future tariff changes are excluded.

Questions answered

Methodology · Report an error