British houses are built to hold heat in. That's a sensible design decision for about ten months of the year, and a miserable one for the other two.
Almost nobody here has air conditioning. So the advice written for people who do, which is most of what you'll find, is of limited use at one in the morning in a bedroom that has been absorbing sun since ten. This is the version for a UK house, in order of what actually makes a difference, starting with your cooling bedding.
Why heat wrecks sleep specifically
Falling asleep depends partly on your core body temperature dropping. That drop is one of the signals your body uses to start the process. A warm room slows or blocks it, which is why you can be exhausted and still lie there fully alert.
The Sleep Charity gives the ideal bedroom range as 16 to 18°C, and notes that above 24°C people become restless. In a UK heatwave, upstairs bedrooms routinely sit in the high twenties well past midnight, because heat rises and brick holds it.
This is not a small problem in the way it's often treated. In Dreams' 2024 UK Sleep Survey, being too hot was the single most cited cause of disturbed sleep, reported by 37% of people. That's a commissioned industry survey rather than peer reviewed research, so treat the number as indicative. It matches what most people already know from experience.
And the heat is not going anywhere. The Met Office recorded the UK's highest ever temperature on 19 July 2022, when 40.3°C was provisionally reached at Coningsby in Lincolnshire, with 46 stations exceeding the previous national record of 38.7°C.
Start during the day, not at bedtime
The most useful thing you can do about your bedroom at midnight happened at eleven in the morning.
Close the curtains and windows on the sunny side, early. Keeping sunlight out of the room is far more effective than trying to remove heat once it's in. If your bedroom faces south or west, it should be shut up from mid morning.
Open everything once the outside air is cooler than the inside. In a UK heatwave that's usually after nine or ten in the evening. Opening windows during the afternoon actively imports heat.
Create a through draught if you can. Two windows open at opposite ends of the house move considerably more air than one open window in the bedroom.
Keep internal doors open overnight. A closed bedroom door traps a small volume of hot air with you in it.
What to do with the bed
This is where most of the practical gain sits, because you can change what's touching you far more easily than you can change the air temperature.
Drop the tog. A 4.5 tog summer duvet instead of a 10.5 makes an immediate difference. Plenty of people sleep under a sheet alone in July and are fine.
Change what your skin is against. Cotton and linen breathe. A cooling surface helps more than people expect, because your face and neck spend the whole night in contact with it. Our cooling ice silk pillowcase is the cheapest useful change you can make here, and a cooling summer quilt covers the duvet problem.
Cool your feet and wrists. Both have a lot of blood vessels close to the surface. A cold flannel on the wrists, or feet out from under the covers, shifts heat faster than anything you do to your torso.
Try the fan properly. A fan doesn't cool air, it moves it, which helps sweat evaporate. Point it across the room rather than directly at your face all night, and put a bowl of ice water in front of it if you want a modest extra effect. Expectations should stay modest.
Have a lukewarm shower, not a cold one. A very cold shower causes blood vessels to constrict, which traps heat. Lukewarm works better.
What isn't worth bothering with
A few things circulate every summer that don't do much.
- Freezing your bedding. It's cold for eleven minutes and then it's a slightly damp duvet.
- Sleeping downstairs, mostly. It's genuinely cooler, but it's usually a worse sleep environment overall, and a sofa costs you more than the temperature saves. Worth it only in the extreme nights.
- Drinking a lot of water right before bed. Stay hydrated across the day. Loading up at eleven produces a different reason to wake at three.
If you share a bed and disagree about temperature
This is one of the most common sources of summer sleep friction, and the usual compromise, meeting in the middle, leaves both people uncomfortable.
The better answer is separate bedding. Two single duvets on a double bed, at different togs, is standard practice in Scandinavia and solves the problem outright. It is far less drastic than it sounds and considerably less drastic than the alternative, which we've written about in our piece on sleep divorce in the UK.
When heat is more than uncomfortable
Hot weather isn't only a sleep quality issue. During official heat health alerts, older adults, very young children, pregnant women and people with heart or breathing conditions are at genuine risk. NHS and UKHSA heat health guidance covers the warning signs of heat exhaustion, and it's worth reading before a heatwave rather than during one.
If you're regularly waking overnight even in normal temperatures, heat isn't your explanation. Our piece on why you keep waking up at 3am covers what else it might be.