Heat pump running cost calculator

Estimate annual electricity from floor area, heat demand and seasonal performance.

Compare systems for the same useful heat. Real SCOP depends on fabric, climate, emitters, flow temperature and hot-water use.

The result is not a supplier bill or quote. Unit rates, standing charges, region, payment method, meter type, tariff, VAT, discounts, debt and support schemes can differ. Use values from the same tariff period and bill for a personal check.

Calculator

Estimate heat-pump electricity

This is not a heat-loss survey or system design.

The calculation runs in your browser. Values are not sent to the website.

How the calculation works

Electricity ≈ floor area × heat demand ÷ SCOP + auxiliary electricity.

Unit-rate energy and daily standing charges are shown separately wherever possible. That prevents a misleading single pence-per-kWh figure.

Worked example in pounds

A 100 m² home at 80 kWh/m²/year and SCOP 3.5 needs about 2,286 kWh plus auxiliaries.

The example checks the method. It is not a universal tariff or a forecast of your next bill.

What changes the result

The largest differences usually come from:

  • heat loss
  • flow temperature
  • SCOP
  • hot water
  • backup heater

How to improve the estimate

Use rates for your region, payment method and meter, including VAT consistently. Match the number of days and do not add standing charges or discounts twice.

Use actual meter readings, separate electricity from gas and compare at least a year for weather-sensitive use. Keep debt repayments and account credit outside consumption cost.

Pre-filled figures are editable, dated reference values with a source.

Frequently asked questions

Will this match my energy bill?

Not necessarily. Regional rates, price changes inside a bill, meter estimates, tariff discounts, debt and rounding can differ.

Does the price cap limit my total bill?

No. It limits rates for covered default tariffs; total cost still rises with energy use.

Sources and review date

Content reviewed on: 2026-08-03.