A hot bedroom is the worst part of a UK heatwave. The house has spent all day soaking up heat, and a British bedroom is not built to let it back out. The good news is you do not need to spend much to fix it. Here is what actually works, roughly in order of cost, from free habits to the kit worth buying. If you want the temperature to aim for, see our guide to how hot is too hot to sleep.
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Start with the free stuff
Before you buy anything, get the basics right. Keep curtains or blinds closed during the day, especially on south and west-facing windows, so the sun is not heating the room while you are out. At night, open windows on opposite sides of the home to pull cooler air through, and leave internal doors open so it can move. Switch off anything that throws out heat, including lamps and gadgets left on standby, and swap heavy bedding for cotton or linen.
Block the daytime sun
If one room bakes every afternoon, the cheapest lasting fix is stopping the sun getting in. Blackout blinds or even a reflective panel in the window keep a surprising amount of heat out, and they help you sleep through bright summer mornings too.
Get the air moving
A fan is the cheapest thing that genuinely helps, and it costs about 1 to 2 pence an hour to run. At night, point it out of an open window to push the hot air out rather than just stirring it around. For the best UK models, see our guide to the best fans for 2026, and for cooling away from the bedroom there are neck fans.
Drop the humidity
Sometimes a room is not just hot, it is sticky, and that is what makes it hard to sleep. Pulling moisture out of the air with a dehumidifier makes a warm room feel more bearable, and it earns its keep again in winter against condensation.
When you need to actually cool the air
If the room overheats no matter what you do, a portable air conditioner is the only thing on this list that lowers the actual temperature rather than just moving air about. It is the priciest option to buy and run, so it is worth understanding how well they really work in UK homes first, then picking from the best portable air conditioners.
Common questions
Does putting ice in front of a fan work?
A bit. A bowl of ice sat in the airflow chills the breeze for a while, but it melts fast and will not cool a whole room. Treat it as a short-term trick, not a fix.
Should I open the windows during the day in a heatwave?
Only if it is genuinely cooler outside than in. On the hottest days, keep windows and curtains shut while the sun is up to keep heat out, then open everything at night once the outside air drops.
What is the cheapest way to cool a bedroom?
A fan, used well, plus the free habits. Closing blinds by day and opening opposite windows at night costs nothing and makes a real difference before you spend on anything.
Do I actually need air conditioning?
Most UK bedrooms get by with a good fan and the free tricks. A portable air conditioner earns its place if your room overheats badly, you work from home in it, or you sleep poorly in the heat.