United Kingdom Living room and office
How much does it cost to run an air purifier?
An air purifier is a fan and a filter. On its lowest setting a HEPA purifier draws 5 to 15 watts, on high 50 to 100. Left on auto around the clock a typical unit averages about 40 watts, a little under 1 kWh a day.
A 40 watt air purifier costs about 1.1p an hour to run in Great Britain at 26.32 pence per kWh. Running it 24 hours a day comes to about 25p a day, £7.69 a month and £92.29 a year.
- Price: Ofgem cap, Oct to Dec 2026
- Wattage range with its source
- Checked 26 October 2026
Uses 0.96 kWh a day, 29 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 40 watt air purifier costs about 1.1p an hour to run in Great Britain at 26.32 pence per kWh. Running it 24 hours a day comes to about 25p a day, £7.69 a month and £92.29 a year.
What this assumes
The default is a 40 watt air purifier running 24 hours a day. Published typical ratings run from 10 to 100 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 24 hours a day |
|---|---|---|---|---|
| 10 watt | 0.3p | 2.1p | 6.3p | 44p |
| 40 watt | 1.1p | 8.4p | 25p | £1.77 |
| 100 watt | 2.6p | 21p | 63p | £4.42 |
How an air purifier uses electricity
The filter does not use energy, the fan does, so a bigger unit on low usually uses less than a small unit on high for the same clean air delivery rate.
Twenty-four hours a day is the normal way to run one, so the hours here are set to 24.
Ways to cut the cost
- Use auto mode so it only speeds up when the sensor sees particles.
- Replace the filter on schedule. A clogged filter makes the fan work harder.
Questions people ask
How much does it cost to run an air purifier 24/7?
At 40 watts, about 0.96 kWh a day, about 17 cents at 18 cents per kWh or 25p at 26.32p per kWh.
Do air purifiers use a lot of electricity?
No. Even on high, most draw less than a large fan.
Other living room and office 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.