Cost to run an extractor fan
An extractor fan drawing 17.2 W costs 0.45p for each hour of running at 26.32p/kWh. Used 1 hour a day, every day, that comes to 13.8p a month.
An hour of running costs
0.45p an hour
That is 0.017 kWh. Used as set, it comes to 13.8p a month and £1.65 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 | 0.45p | 0.017 kWh | 3.7 g |
| A day, on average | 0.45p | 0.017 kWh | 3.7 g |
| A month | 13.8p | 0.52 kWh | 114 g |
| A year | £1.65 | 6.27 kWh | 1.4 kg |
How we calculated this
Energy is power multiplied by time: 17.2 W running for an hour uses 0.017 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 the fan motor’s, worked out from each model’s airflow and efficacy: the median certified bathroom fan moves 100 cubic feet a minute. The figure Centre for Sustainable Energy gives for an extractor fan is close to it.
The starting use for an extractor fan, 1 hour 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 extractor fan draws only 17.2 W while it runs, and it is on for short spells, so it costs £1.65 a year at 1 hour a day, every day. It is one of the cheapest things in the house to run and one of the most useful against damp.
Also called: bathroom fan, ventilation fan, exhaust fan, bathroom extractor.
What it costs in the UK, Europe and the US
For an extractor fan used as typical (1 hour a day, every day), at each country’s published average electricity price.
| Country | Electricity price | An hour |
|---|---|---|
| United Kingdom | 26.32p/kWh | 0.45p |
| United States (average) | 18.19¢/kWh | 0.31¢ |
| Ireland | €0.4042/kWh | €0.0069 |
| Germany | 0,3869 €/kWh | 0,0067 € |
| France | 0,2561 €/kWh | 0,0044 € |
| Spain | 0,2669 €/kWh | 0,0046 € |
| Italy | 0,2966 €/kWh | 0,0051 € |
| Netherlands | € 0,2558/kWh | € 0,0044 |
Compared with similar appliances
| Appliance | Typical power | An hour | A year, typical use |
|---|---|---|---|
| Extractor fan | 17.2 W | 0.45p | £1.65 |
| Cooker hood | 32.6 W | 0.86p | £3.13 |
| Dehumidifier | 500 W | 13.2p | £288.20 |
| Ceiling fan | 17.3 W | 0.46p | £7.09 |
How to spend less on it
- Run it while you shower or cook and for a short while after, so the damp is gone before it can settle: it costs far less than dealing with mould.
- Clean the grille and blades now and then: a clogged fan moves less air for the same power.
Questions
How much does an extractor fan cost to run per hour?
At 26.32p/kWh, an extractor fan drawing 17.2 W costs 0.45p for every hour of running at full power.
How much does an extractor fan cost to run a year?
Used 1 hour a day, every day, it costs about £1.65 a year at 26.32p/kWh, or 13.8p a month.
How many watts does an extractor fan use?
Most draw between 9 W and 28.3 W while running, and 17.2 W is typical. The rating is on the label or in the manual.
Is it worth running an extractor fan?
Yes: at 17.2 W it costs 0.45p an hour, a small price against the cost of damp and mould. Run it while you produce steam and a little after.
Sources
- ENERGY STAR Certified Ventilating Fans (open data), ENERGY STAR, US Environmental Protection Agency, 26 September 2026. “ENERGY STAR certified bathroom and utility room fans, motor power: median 17.2 W across 971 certified models, 10th to 90th percentile 9.01 W to 28.3 W (models where unit_type='Bathroom/Utility Room').”
- How much electricity am I using?, Centre for Sustainable Energy, July 2026. “Extractor fan (20 W)”
More calculators
- What appliances cost to run
Every appliance side by side, by category.
- Electricity cost calculator
Any appliance, from its wattage.
- Whole-home estimator
Add up everything you run, and check it against your bill.
- Electric car charging
What charging at home costs, against petrol or diesel.
- Heat pump or gas boiler
Running costs, payback and emissions.
- Battery backup
How long a home battery runs your essentials in a power cut.
- Solar panels
System size, production and payback for your roof.