United Kingdom Heating
How much does it cost to run an air source heat pump?
A heat pump moves heat instead of making it, so each kilowatt hour of electricity delivers two to four kilowatt hours of heating or cooling. That is why a 1,200 watt mini split can heat a room that would need a 3,000 watt resistance heater.
A 1.2 kW air source heat pump costs about 22p an hour to run in Great Britain at 26.32 pence per kWh. Running it 8 hours a day cycling 70% of the time comes to about £1.77 a day, £53.83 a month and £646.02 a year.
- Price: Ofgem cap, Oct to Dec 2026
- Wattage range with its source
- Checked 26 October 2026
Uses 6.7 kWh a day, 205 kWh a month, at 26.32 pence per kWh (Great Britain (price cap average)).
The dial places the daily cost between a 50 watt fan and a 4.5 kW water heater on 2.5 hours a day.
A 1.2 kW air source heat pump costs about 22p an hour to run in Great Britain at 26.32 pence per kWh. Running it 8 hours a day cycling 70% of the time comes to about £1.77 a day, £53.83 a month and £646.02 a year.
What this assumes
The default is a 1.2 kW air source heat pump running 8 hours a day, drawing full power 70% of the time it is switched on (the rest of the time a thermostat or sensor has it idle). Published typical ratings run from 600 to 2,500 watts. Your label or manual gives the exact figure, and the calculator takes it.
The price is the Ofgem price cap unit rate for 1 October to 31 December 2026, average for England, Scotland and Wales, paying by Direct Debit. The cap for 1 January to 31 March 2027 is announced in late November 2026. A fixed tariff, a time-of-use plan or a different payment method changes the rate, which is why the rate field is editable.
Cost by wattage and hours at the price cap rate
At 26.32p per kWh, running flat out. Multiply by the share of the time your thermostat keeps the element on.
| Power | 1 hour | 8 hours | 24 hours | A week at 8 hours a day |
|---|---|---|---|---|
| 600 watt | 16p | £1.26 | £3.79 | £8.84 |
| 1.2 kW | 32p | £2.53 | £7.58 | £17.69 |
| 2.5 kW | 66p | £5.26 | £15.79 | £36.85 |
How an air source heat pump uses electricity
A single-zone mini split draws roughly 600 to 1,500 watts while running, and modulates its compressor rather than switching fully on and off, so the duty cycle is smoother than a plug-in heater. A whole-house ducted heat pump draws 2,000 to 5,000 watts.
Output falls as the outdoor temperature drops, so running cost per hour rises in a cold snap even though the rated input stays the same. Modern cold-climate units keep a coefficient of performance above 2 well below freezing.
For the UK, a 3 to 4 kW whole-house air source heat pump is sized to the house, runs for long hours at low output and is usually compared with a gas boiler at the Ofgem gas rate rather than with plug-in heaters.
Ways to cut the cost
- Set it and leave it. Heat pumps are most efficient at a steady temperature, not on timers.
- Clean the filters monthly in season.
- Keep the outdoor unit clear of leaves and snow.
Questions people ask
Is a heat pump cheaper to run than a space heater?
Yes, by roughly the coefficient of performance. A heat pump delivering 3 kWh of heat per kWh of electricity costs about a third as much as resistance heat for the same warmth.
How much does a mini split cost to run per month?
At 1,200 watts, 70% duty and 8 hours a day, about 200 kWh a month. At 18 cents that is about 36 dollars. Change the hours and rate above for your case.
Other heating costs
More in the UK
Sources
The electricity price on this page is read from the data file that also lists the release it came from. The wattage range is a published typical range, not a measurement of your appliance.