The short answer
A fan is far cheaper per hour — often well under 2p — but it only moves air; it does not lower the room temperature. Air conditioning costs about 15–25p per hour for a 2.5 kW split, because it actively removes heat. So the cheaper option depends entirely on whether you need real cooling or just a cooling breeze. They are not interchangeable on cost alone.
“Should I just use a fan?” is a fair question when energy prices bite, but it only makes sense once you understand that a fan and air conditioning do different jobs. A fan moves air to help your skin feel cooler; air conditioning lowers the air temperature itself. This page compares their running costs honestly and explains when each is the right, cheaper choice.
Air con vs fan at a glance
- Fan per hour Usually well under 2p
- 2.5 kW split per hour ~15–25p
- Fan effect Moves air, no temperature drop
- Air con effect Removes heat, lowers temperature
- Cheaper for a breeze Fan
The cost difference, plainly
A typical electric fan draws only tens of watts — a small fraction of a kilowatt — so it usually costs well under 2p per hour to run. A 2.5 kW air-conditioning split draws roughly 0.6–1.0 kWh per hour, costing about 15–25p per hour at a 25p/kWh unit rate. On a pure per-hour basis the fan wins comfortably, often by a factor of ten or more. If your only question is “which device uses less electricity per hour”, the answer is unambiguously the fan.
| Device | Power drawn | Cost per hour (25p/kWh) |
|---|---|---|
| Electric fan | Tens of watts | Usually under 2p |
| 2.5 kW split (cooling) | 0.6–1.0 kWh | ~15–25p |
| Portable air con | Often higher than a split | More than 25p typical |
But they do different jobs
The cost comparison is only fair if the two devices delivered the same result — and they do not. A fan moves air across your skin, which speeds the evaporation of sweat and makes you feel cooler, but it does not remove heat from the room; on a very hot day it can simply circulate warm air around. Air conditioning actively extracts heat and lowers the air temperature, something a fan can never do. So the “cheaper” option depends entirely on what you actually need from it: a breeze, or a genuine drop in temperature.
- Fan — cheap, moves air, no real temperature drop.
- Air con — dearer, removes heat, genuinely cools the room.
- On a very hot day a fan alone may not be enough to stay comfortable.
When each is the right choice
For a mild warm day, or to feel a breeze while you sleep, a fan is the obvious low-cost answer and there is no reason to run air conditioning. When the room is genuinely too hot to be comfortable — or you need to control temperature for sleep, work or a health reason — air conditioning earns its higher running cost by doing something a fan cannot. Many households use both: the fan for ordinary days and the air con reserved for the hottest spells, which keeps the overall bill down while still giving real cooling when it counts.
Keeping the air con bill sensible
If you do choose air conditioning, the Energy Saving Trust’s efficiency principles keep its cost in check: size the unit correctly, set a moderate temperature, shade the room and run it only when you need real cooling. Running a fan to circulate the cooled air can also let you set the air con a little warmer, lowering its draw. Used selectively alongside a fan, a split system need not be expensive. For the detail see running cost and the cheapest way to run air con.
A fair way to compare the two
The honest comparison is not “which is cheaper” but “which does the job you need at the lowest cost”. If the room is merely a little warm and you want air movement, the fan wins outright: it costs a fraction of a penny per hour and a 2.5 kW split would be overkill. If the room is genuinely too hot — the kind of heat that disturbs sleep or makes work difficult — a fan cannot fix it at any price, because it does not remove heat, and air conditioning is the only option that delivers what you need. Framed that way, the two are partners rather than rivals: the fan handles the many mild days cheaply, and the air con is held in reserve for the few genuinely hot ones. Run that way across a UK summer, your total cooling bill stays low because the expensive device only works on the days it is truly earning its keep.
These are typical 2026 estimates for guidance; your real cost depends on the specific devices and your tariff.
Match the device to the need
Use a fan for a breeze on milder days and reserve air conditioning for when you genuinely need the room temperature to drop.
Frequently asked questions
Is a fan cheaper than air con?
Yes, far cheaper per hour — usually well under 2p against 15–25p for a 2.5 kW split — but a fan only moves air and does not lower the room temperature.
Does a fan cool a room like air con?
No. A fan makes your skin feel cooler by moving air, but it does not remove heat. Only air conditioning actually lowers the air temperature.
When is air con worth the extra cost over a fan?
When the room is genuinely too hot for a fan to help, or you need controlled temperature for sleep, work or health. On milder days a fan is the cheaper, adequate choice.
Can I use a fan and air con together?
Yes, and it can be efficient: run the fan to circulate the cooled air so the air con can be set to a moderate temperature, keeping the overall bill lower.
Sources & further reading
- Ofgem — typical domestic electricity unit rates
- Energy Saving Trust — cooling and efficiency guidance
- Manufacturer technical data (e.g. Daikin, Mitsubishi Electric) — power input specifications
- gov.uk — staying cool and household energy information
This guide is general information, not a site-specific survey or a substitute for a quote from an F-Gas-certified installer. Installation, servicing and refrigerant handling are legally restricted to F-Gas-certified engineers.