Show the formula and working
This fan running cost calculator shows what an electric fan costs to run per hour, per day and over a whole summer. Enter the fan power in watts, how many hours a day it runs, how many days you use it and how many fans you have. It starts with the UK price cap unit rate, has EU presets, and you can type your own tariff.
Quick answer: A fan costs its power in kW times the hours it runs times your unit rate. A 40 W fan costs about 1.05p an hour at 26.32p, so running it for 8 hours a night costs about 8p, and 60 nights cost about £5.05. Even left on for 24 hours, a 40 W fan costs about 25p.
How Is Fan Running Cost Calculated?
Divide the fan wattage by 1,000 to get kilowatts, multiply by the hours it runs and by your unit rate.
Fans use very little power compared with heaters and air conditioners, because they only move air with a small motor. They do not cool the air: they make you feel cooler by moving air over your skin. The calculator multiplies the power by the number of fans and the hours a day for the daily kWh, then by your unit rate for the daily cost. Multiplied by your days of use, that gives the cost for the summer. It also shows how many hours of running £1 buys.
The power shown on the label is usually the highest speed. Lower speeds use less, so if you mostly run the fan on a low setting your real cost will be a little lower.
How Do You Use the Fan Calculator?
- Enter the fan power from its label.
- Enter how many hours a day the fan runs.
- Enter how many days a year you use it.
- Enter how many fans you run.
- Choose a price preset or enter your unit rate.
How Much Does a Fan Cost to Run?
At 26.32p per kWh, a fan costs about 0.26p an hour for every 10 W of power, so even a large 100 W fan costs under 3p an hour.
| Fan power | Cost per hour | Cost per 8 hour night | Cost per summer (60 days) | Hours for £1 |
|---|---|---|---|---|
| 20 W | 0.53p | 4p | £2.53 | 190 |
| 40 W | 1.05p | 8p | £5.05 | 95 |
| 60 W | 1.58p | 13p | £7.58 | 63 |
| 100 W | 2.63p | 21p | £12.63 | 38 |
Desk and pedestal fans are often around 20 to 60 W, while tower fans and larger floor fans vary more. Check the label on the base or back of your fan. The 26.32p figure is the Ofgem price cap average for October to December 2026, which you can check on the Ofgem energy price cap page.
Is It Expensive to Run a Fan All Night?
No. A typical 40 W fan running from 11pm to 7am uses 0.32 kWh, which is about 8p a night at 26.32p.
Left on for a full 24 hours, the same fan uses 0.96 kWh, about 25p. That is why fans are one of the cheapest ways to feel cooler at night. Many fans have a timer or sleep mode that switches them off after you fall asleep, which cuts the cost further.
Fan or Air Conditioner?
A fan costs a small fraction of what a portable air conditioner costs to run, but it does not lower the room temperature.
A portable air conditioner often draws around a kilowatt or more, many times more than a fan. In a typical UK summer, most homes can stay comfortable with fans, shading and opening windows at cooler times of day. If you are thinking about an air conditioner, the air conditioner running cost calculator shows what it would cost. For a permanent option, the ceiling fan size calculator helps choose the right size for a room.
Worked Example: Three Fans in a Heatwave
Example: a family runs three 35 W fans, one in each bedroom, for 10 hours a day during a 45 day hot spell, at the 26.32p price cap rate.
- Power: 3 x 35 W = 105 W, or 0.105 kW
- Per day: 0.105 kW x 10 h = 1.05 kWh, about 28p
- Per summer: 1.05 kWh x 45 days = 47.25 kWh
- Cost: 47.25 kWh x 26.32p = £12.44
So keeping three bedrooms comfortable through a long hot spell costs about the same as a takeaway coffee or two a month. The bigger question is usually noise and air flow rather than cost.
Tips to Keep Cool for Less
A few habits help a fan do more with less.
- Close curtains or blinds on sunny windows during the day.
- Open windows when the air outside is cooler, such as early morning and late evening.
- Place the fan so it moves air across you, not just around the room.
- Use the timer or sleep mode so the fan does not run all night if you do not need it.
- Switch fans off in empty rooms: a fan cools people, not rooms.
Fan Running Cost FAQs
How much does a fan cost per hour?
A fan costs its power in kW times your unit rate. At 26.32p, a 40 W fan costs about 1.05p an hour and a 100 W fan about 2.63p.
How much does it cost to run a fan all night?
A 40 W fan running for 8 hours uses 0.32 kWh, about 8p at 26.32p. A full 24 hours costs about 25p.
Do tower fans use more electricity?
Not always. Tower fans often use a similar power to pedestal fans. Check the wattage label on your fan.
Is a fan cheaper than air conditioning?
Yes, by a large margin. A fan uses tens of watts, while a portable air conditioner often uses around a kilowatt or more.
Does a fan cool the room?
No. A fan moves air over your skin, which helps you feel cooler. The motor gives off a little heat, so switch it off when the room is empty.
Do DC fans cost less to run?
Fans with DC motors are often described as using less power than AC fans. Use the wattage on your fan’s label in the calculator.
Checked October 2026. Sources: Ofgem energy price cap. Fan wattages are examples; use your fan’s label.