The cheapest way to cool a bedroom in the UK
Four realistic options, what each costs to buy, and what each costs to run for a night. We're air conditioning installers, so we'll be straight with you: for a lot of people a £40 fan is the right answer. For anyone who can't sleep from May to September, it isn't.
Pedestal or tower fan
Moves air, doesn't cool it. Fine when the room is 22–24°C, useless in a 28°C loft bedroom. Cheapest option by miles and worth owning regardless.
Evaporative (swamp) cooler
Adds moisture to the air. In the UK's humid summers it barely drops the temperature and can make a bedroom feel clammy. We'd skip it.
Portable air conditioner
Does genuinely cool, but you need the window cracked open for the hose — which lets heat and noise straight back in. Loud (48–55 dB), bulky, and you store it for nine months a year.
Fitted wall split system
Quietest (around 19 dB — under the sound of a fridge), cheapest to run, cools the room in 10 minutes and heats it cheaper than your boiler in spring and autumn. The only permanent fix.
The honest answer
If you get two or three bad nights a year, buy a fan and blackout blinds. If your bedroom is a south-facing loft, a converted attic or a modern well-insulated new build that holds heat all night, nothing except a fitted split system will actually fix it — and the running cost is lower than the portable you were considering. It also heats the room in winter for less than your gas boiler. Work out your own running cost →
Bedroom air con from £1,950 fitted
One day on site, no mess, F-Gas certified. Send a photo of the room and we'll give you a ballpark the same day.
Common questions
What's the cheapest way to cool a bedroom right now?
A fan plus blackout blinds and closing windows during the day. It costs under £50 and takes the edge off. It won't drop the room temperature though — it only makes you feel a couple of degrees cooler.
Is a portable air conditioner cheaper than a fitted one?
Cheaper to buy, dearer to own. A £500 portable uses roughly 2–3× the electricity of a fitted split for the same cooling, so over five summers the running cost gap alone is several hundred pounds — before you count the noise and the lost window.
How much does it cost to run air conditioning overnight?
A correctly sized 2.5kW inverter unit holding a bedroom at 20°C draws roughly 0.3–0.6 kWh per hour of actual compressor time. On a typical UK summer night that's about 12–25p for the whole night.
Can you fit air conditioning in a small bedroom?
Yes — most bedrooms need a 2.0–2.6kW unit. It's a one-day job, we do it clean with dust sheets, and it's from £1,950 fully fitted including the F-Gas certificate.