FREE UK HEAT PUMP CALCULATOR
Heat Pump Running Cost Calculator
Estimate daily, monthly and annual air-source heat pump running costs using your own electricity tariff and measured electricity use—or calculate electricity from useful heat and an assumed COP or SCOP.
ESTIMATED RUNNING COST
£112.50 over 30 days
15.00 kWh/day × 25.00p/kWh
Daily
£3.75
7 days
£26.25
30 days
£112.50
365 days
£1,368.75
Estimated period electricity: 450.00 kWh
Annualised electricity at the same average use: 5,475.00 kWh
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How to estimate heat pump electricity costs
If you have a dedicated electricity reading, use that. Running cost equals electricity used (kWh) × tariff (£/kWh). You can enter daily or annual electricity use. For example, 15 kWh/day at 25p/kWh costs £3.75 per day, while 5,475 kWh/year at the same rate costs £1,368.75 per year.
If you only know useful heat delivered, divide delivered heat (kWh) by the COP or SCOP that represents the same period to estimate electricity consumption. A COP of 3 means approximately 3 kWh of useful heat per 1 kWh of electricity in that period. A seasonal SCOP is usually the more appropriate basis for an annual heat-demand calculation.
Worked annual heat pump cost example
If a home needs 12,000 kWh of useful heat over a year and the heat pump achieves a SCOP of 3.0, estimated electricity use is 12,000 ÷ 3.0 = 4,000 kWh. At an illustrative electricity price of 25p/kWh, that is about £1,000 per year in variable electricity cost before standing charges and other household electricity.
The same arithmetic shows why efficiency matters: at the same 12,000 kWh heat demand and tariff, a SCOP of 4.0 would use about 3,000 kWh instead. Treat these as examples, not expected performance for a particular property or installation.
Why actual bills may differ
Heat demand and efficiency change with outdoor temperature, hot-water use, schedules, home insulation, target temperature, backup heating and defrost cycles. Some heat-pump monitors omit auxiliary equipment. Time-of-use tariffs need separate calculations for the kWh bought at each rate. The calculator is a planning illustration—not a prediction of your actual bill.
Frequently asked questions
How do I calculate annual heat pump running cost?
Estimate the heat pump's annual electricity use and multiply it by your electricity unit price. If starting from annual useful heat demand, divide the heat demand by the annual or seasonal efficiency first.
How do I calculate electricity use from SCOP?
Divide useful heat demand by SCOP. For example, 12,000 kWh of useful heat at SCOP 3.0 is approximately 4,000 kWh of electricity.
What is the difference between COP and SCOP?
COP describes efficiency at a particular operating condition or shorter period. SCOP is a seasonal average. Match the efficiency figure to the same period as the heat-demand figure.
Does the calculator include electricity standing charges?
No. It estimates variable electricity cost attributable to the heat pump from the kWh and tariff entered. Standing charges and other household electricity are excluded.
Why might my actual bill differ?
Weather, indoor temperature, hot-water use, flow temperature, controls, defrost cycles, backup heating and metering scope can all change actual consumption and cost.
Heat pump using more electricity than expected?
Compare similar weather and comfort requirements before adjusting controls. Record the tariff, meter period, heating and hot-water schedules, indoor target and any error messages. Read the free UK heat pump owner troubleshooting guides for a structured approach.