Cost to run an air purifier
An air purifier drawing 25.9 W costs 0.68p for each hour of running at 26.32p/kWh. Used 16 hours a day, every day, that comes to £3.31 a month.
An hour of running costs
0.68p an hour
That is 0.026 kWh. Used as set, it comes to £3.31 a month and £39.76 a year.
On the label or in the manual.
Standby, thermostats and off-peak use
A thermostat switches it on and off to hold a temperature. 100% if it runs flat out.
Drawn while plugged in and not running.
| Period | Cost | Energy | CO2e |
|---|---|---|---|
| An hour of running | 0.68p | 0.026 kWh | 5.6 g |
| A day, on average | 10.9p | 0.41 kWh | 90 g |
| A month | £3.31 | 12.6 kWh | 2.7 kg |
| A year | £39.76 | 151 kWh | 32.8 kg |
How we calculated this
Energy is power multiplied by time: 25.9 W running for an hour uses 0.026 kWh.
The figures are for ENERGY STAR certified models sold in the US and Canada. Certified models are more efficient than the average model on sale, and many are larger than the ones sold in Europe, so an older or less efficient one will use more. The power is ENERGY STAR’s annual figure divided by the 16 hours a day of active operation it assumes, and the starting use is the same 16 hours a day. The median certified purifier is rated for a room of 250 square feet; a bigger one draws more.
The starting use for an air purifier, 16 hours a day, every day, is where the calculator starts, not a measurement of your home: change it to how you use yours. A day is the average across the week, and a month is a twelfth of a 365-day year.
Electricity costs 26.32p/kWh. That is the published figure for the United Kingdom, 1 Oct – 31 Dec 2026, from Ofgem. Average for England, Scotland and Wales, paying by Direct Debit. No VAT on electricity from 1 October 2026 to 31 March 2027.
Standing charges are left out: you pay them whether or not the appliance runs.
Emissions use 0.217 kg CO2e per kWh, the lifecycle intensity of electricity generated in the United Kingdom in 2025, from Ember, via Our World in Data. Lifecycle means building the power stations and supplying their fuel are counted too. It is the grid’s average, not the particular power station an extra appliance brings on.
What drives the cost
An air purifier runs a fan through a filter, and it draws 25.9 W at the median of 246 certified models, for a room of 250 square feet. It is meant to run for hours, so what it costs is mostly the hours: at 16 hours a day, every day, an air purifier costs £39.76 a year at 26.32p/kWh.
Also called: air cleaner, HEPA air purifier, room air cleaner.
What it costs in the UK, Europe and the US
For an air purifier used as typical (16 hours a day, every day), at each country’s published average electricity price.
| Country | Electricity price | An hour |
|---|---|---|
| United Kingdom | 26.32p/kWh | 0.68p |
| United States (average) | 18.19¢/kWh | 0.47¢ |
| Ireland | €0.4042/kWh | €0.01 |
| Germany | 0,3869 €/kWh | 0,01 € |
| France | 0,2561 €/kWh | 0,0066 € |
| Spain | 0,2669 €/kWh | 0,0069 € |
| Italy | 0,2966 €/kWh | 0,0077 € |
| Netherlands | € 0,2558/kWh | € 0,0066 |
Compared with similar appliances
| Appliance | Typical power | An hour | A year, typical use |
|---|---|---|---|
| Air purifier | 25.9 W | 0.68p | £39.76 |
| Dehumidifier | 500 W | 13.2p | £288.20 |
| Ceiling fan | 17.3 W | 0.46p | £7.09 |
| Extractor fan | 17.2 W | 0.45p | £1.65 |
How to spend less on it
- Match it to the room: one rated for a bigger room draws more than a small room needs.
- Run it on a lower speed when you do not need it working hard, and clean or change the filter as the maker advises: a clogged filter makes the fan work harder.
- Keep doors and windows closed while it runs, so it is cleaning the same air rather than fresh air from outside.
Questions
How much does an air purifier cost to run per hour?
At 26.32p/kWh, an air purifier drawing 25.9 W costs 0.68p for every hour of running at full power.
How much does an air purifier cost to run a year?
Used 16 hours a day, every day, it costs about £39.76 a year at 26.32p/kWh, or £3.31 a month.
How many watts does an air purifier use?
Most draw between 9.4 W and 58.9 W while running, and 25.9 W is typical. The rating is on the label or in the manual.
How much does it cost to run an air purifier all day?
At 25.9 W it costs 0.68p an hour, so at 16 hours a day, every day, an air purifier costs 10.9p a day and £39.76 a year at 26.32p/kWh. Across models most draw between 9.4 W and 58.9 W.
Sources
- ENERGY STAR Certified Room Air Cleaners V3.0 (open data), ENERGY STAR, US Environmental Protection Agency, 26 September 2026. “ENERGY STAR certified room air cleaners, power while running: median 25.9 W across 246 certified models, 10th to 90th percentile 9.42 W to 58.9 W.”
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