Key takeaways
- A 45W tower fan costs about 9p for eight hours, roughly £2.82 over 30 summer nights
- A DC motor model at 25W on medium halves that to about 5p a night
- A portable air conditioner costs roughly £1.25 a night, about thirteen times a tower fan
- Fans cool people, not rooms, so a fan running in an empty room is pure waste
- Noise matters more than airflow at 3am; look for a quoted dB figure at the lowest speed
Tower fans worth the shelf space
All of these cost pennies a night. Buy on noise at the lowest speed, not on airflow.
Amazon partner links — we may earn a small commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Prices and ratings checked on 28 August 2026 and they move, so treat them as a guide rather than a quote. We pick on published specs, wattage and buyer ratings; we do not test appliances ourselves and we say so rather than pretending otherwise.
The short answer
Fans are the cheapest cooling you can buy and it is not close. A tower fan rated at 45W running for eight hours uses 0.36kWh, which costs 9p at the 26.11p per kWh cap rate. Thirty warm nights, which is a generous estimate for a British summer, comes to about £2.82.
You could leave one running every night from June to August and it would cost less than a takeaway. This page exists mostly so you can stop worrying about it and go and look at the things that actually matter, like whether your loft insulation is stopping the roof cooking your bedroom.
Running costs by fan type
Eight hours a night at 26.11p per kWh. The seasonal column assumes 30 nights.
| Fan | Typical power | 8 hours | Per night | 30 nights |
|---|---|---|---|---|
| Desk fan | 20W | 0.16kWh | 4.2p | £1.25 |
| DC tower fan, medium | 25W | 0.20kWh | 5.2p | £1.57 |
| Bladeless tower | 40W | 0.32kWh | 8.4p | £2.51 |
| AC tower fan | 45W | 0.36kWh | 9.4p | £2.82 |
| Pedestal fan | 50W | 0.40kWh | 10.4p | £3.13 |
Worked example: 45W is 0.045kW, eight hours gives 0.36kWh, and 0.36 × 26.11p = 9.4p.
Against the alternatives
| Method | Per night, 8 hours | Purchase price | Cools the room? |
|---|---|---|---|
| Tower fan | 9p | £30–£120 | No, cools you |
| Evaporative "air cooler" | 10–15p | £80–£200 | Barely, and adds humidity |
| Portable air conditioner | £1.25 | £300–£700 | Yes |
| Fixed split air conditioning | 60–90p | £1,500–£3,000 fitted | Yes, properly |
Evaporative coolers deserve their own warning. They work by evaporating water into the air stream, which cools the air and raises its humidity. In a dry climate that trade is worth making. In a British summer, where humidity is already high on the days you want cooling, they take a few degrees off the air stream and make the room feel clammier. They are not air conditioners and the marketing that implies otherwise is doing a lot of work.
The free version
Close curtains and blinds on the sunny side during the day, open windows on both sides of the house once the outside air is cooler than the inside, and shut everything again before the sun comes round. In a well-insulated house that alone keeps bedrooms several degrees down. Insulation works in both directions: a loft that keeps heat in during January keeps the roof's heat out in July.
What to look for
Noise at the lowest speed. This is the one that matters and the one manufacturers are vaguest about. Around 35dB is fine to sleep next to. Above 45dB you will notice it. Assume any quoted figure is for the quietest setting.
A timer. Two to eight hours with a shut-off means you are not running a fan at 6am in an empty bed. This is where the small saving actually comes from.
DC motor, if the budget stretches. Not for the electricity, which is a couple of pounds a summer, but because you get genuinely low speeds. AC motors have three or four steps and the lowest one is often still too much for a bedroom.
Oscillation angle and height. A 90 degree sweep across a bed is more useful than a 60 degree sweep at a wall. Height matters for sitting versus lying down.
Things not to pay for: air purification claims on a fan, since a fan does not have a HEPA filter and if you want air purification you should buy the machine that does it. Also ionisers, which do little and can produce ozone.
A fan in an empty room is worse than nothing
The motor turns its 45W into heat, all of which stays in the room. Cooling comes from air moving across skin, so with nobody there the fan is a small heater with a good reputation. Use the timer.
Common questions
How much does a tower fan cost to run overnight?
About 9p. A typical tower fan is rated 45W, so eight hours uses 0.36kWh, and at the 26.11p per kWh Ofgem cap rate that is 9.4p. Over 30 warm nights in a British summer you are looking at about £2.82. A DC motor model on a medium setting draws nearer 25W and costs about 5p a night.
Are tower fans cheaper to run than air conditioning?
Enormously. A 9,000 BTU portable air conditioner draws around 1kW and, allowing for cycling at roughly 60% duty over an eight-hour night, uses about 4.8kWh, costing £1.25. The tower fan uses 0.36kWh and costs 9p. That is about thirteen times the running cost, before you count the several hundred pounds difference in purchase price.
Do fans actually cool a room?
No. A fan motor adds a small amount of heat to a room, so a fan running in an empty room makes it very slightly warmer. What a fan does is move air across your skin, which speeds up evaporation and convection and makes you feel several degrees cooler than the thermometer says. That is why leaving one running when you go out is genuinely pointless, and why a timer is the most useful feature on the box.
What is the difference between an AC and a DC motor fan?
DC motors are more efficient and allow much finer speed control. A DC tower fan on a low setting can draw 5 to 10W where an AC model's lowest speed is nearer 30W. They are usually quieter at matched airflow and cost £30 to £60 more. Over a summer the electricity saving is a couple of pounds, so buy one for the quietness and the speed range rather than the running cost.
How loud is too loud for a bedroom fan?
Look for a quoted figure of around 35dB or below at the lowest speed. For reference, 30dB is roughly a quiet library, 40dB is a fridge hum and 50dB is a normal conversation across a room. Manufacturers usually quote the lowest speed and not the highest, so a fan advertised at 35dB may well be pushing 55dB flat out. Bladeless designs are not automatically quieter, they just shift the noise to a different pitch.
Is a tower fan or a pedestal fan better?
A pedestal fan moves more air for its wattage because it has a bigger blade turning slower, and it directs that air where you point it. A tower fan takes up less floor space, oscillates over a wider arc and is generally tidier to look at. For a bedroom where you want gentle background movement, tower. For a hot kitchen or a home office where you want a strong stream on you, pedestal.
Sources and assumptions
Unit rates are the Ofgem default tariff cap for 1 July to 30 September 2026, direct debit, averaged across England, Scotland and Wales including VAT: Ofgem energy price cap. Wattages are the manufacturer ratings printed on the appliance plate or in the product listing; we have not lab-tested anything. Where an appliance cycles rather than drawing full power continuously, we say so and show the duty cycle we used. Check the plate on your own unit before trusting any of these numbers for your house.