Key takeaways
- Around 55% of UK homes, about 15.7 million, would fail a night-time bedroom overheating test in today’s climate, on modelling commissioned by the Climate Change Committee.
- In the English Housing Survey, 1.9 million households (8%) said part of their home gets uncomfortably hot, and 51% of them named the bedroom as the worst room.
- England recorded 2,985 heat-associated deaths in 2022, the highest on record, the year the country first passed 40°C.
- The Sleep Charity puts a comfortable bedroom at 16 to 18°C, yet the overheating threshold used in building studies is 26°C at night, a gap most homes cross in a heatwave.
Every time the UK gets a hot spell, the same question trends: why can’t I sleep when it’s this warm, and is my house worse than most? We pulled together the public data on overheating in British homes to answer that, with a focus on the room it matters most, the bedroom. The figures below come from government surveys, the Climate Change Committee and the UK Health Security Agency, compiled here by lookinto.co.uk Research.
The short version: bedroom overheating isn’t a fringe problem, and it’s getting worse. Here’s what the numbers say.
How many UK bedrooms overheat
The clearest single figure comes from a report Arup carried out for the Climate Change Committee. It modelled a range of typical UK home types against a night-time bedroom overheating test, using a fixed threshold of 26°C. In today’s climate, around 55% of the housing stock fails that test. That’s roughly 15.7 million homes where bedrooms get too hot to sleep well on a warm night. By 2050, on the same modelling, 92% of homes would fail if nothing changes.
People report the same thing when asked directly. In the English Housing Survey for 2020 to 2021, 1.9 million households, about 8%, said at least one part of their home gets uncomfortably hot. More than half of them, 51%, pointed to the bedroom as the room that overheats. So the modelling and the lived experience line up: the bedroom is the problem room.
The numbers at a glance
| Measure | Figure | Source |
|---|---|---|
| UK homes failing a 26°C night-time bedroom overheating test (current climate) | 55% (15.7 million) | Arup for the CCC, 2022 |
| UK homes projected to fail by 2050 if no action taken | 92% | Arup for the CCC, 2022 |
| Households reporting part of the home gets uncomfortably hot | 1.9 million (8%) | English Housing Survey 2020-21 |
| Of those, share naming the bedroom as worst | 51% | English Housing Survey 2020-21 |
| Heat-associated deaths in England, 2022 | 2,985 (highest on record) | UKHSA heat mortality report 2022 |
| Highest temperature recorded in England | 40.3°C (July 2022) | Met Office |
| Comfortable bedroom temperature for sleep | 16 to 18°C | The Sleep Charity |
Why bedrooms are the worst room
A few things stack up against bedrooms. They’re usually upstairs, and heat rises through a house over the day. They catch the evening and overnight warmth after a hot day, which is exactly when you’re trying to sleep. And a lot of UK housing was built to hold heat in for winter, with small windows and limited ventilation, so once a bedroom warms up it stays warm.
That matters because of how sleep works. Your core body temperature needs to drop slightly to fall and stay asleep, and a hot room makes that harder. Studies that measure sleep against summer indoor temperatures find quality drops as bedrooms warm, which is why a 26°C night feels so different from an 18°C one even when you’re tired.
How we compiled this
This is a synthesis of existing public data, not new fieldwork. We took the overheating modelling from the Arup report commissioned by the Climate Change Committee, the self-reported figures from the government’s English Housing Survey, the mortality figures from the UK Health Security Agency’s heat mortality monitoring report, and the temperature record from the Met Office. The bedroom comfort range is from The Sleep Charity. Where a figure depends on a threshold, we’ve stated it: the overheating test uses 26°C measured in bedrooms overnight, a standard used in UK building studies.
The catch with any overheating figure is that it depends on the threshold and the weather year you model, so treat the percentages as a clear direction of travel rather than a precise count. The direction is not in doubt: more UK bedrooms are crossing into uncomfortable territory, more often.
What you can do about it
You can’t change the housing stock, but you can change how a bedroom behaves on a hot night. Keeping daytime sun out, getting air moving at night and managing what’s on the bed all help. We cover the practical side in our guides on how to cool a bedroom in a heatwave and how to sleep in a heatwave. On the bedding side, a cooling mattress topper can help you shed body heat faster, though as we explain it won’t lower the room temperature on its own.
FAQ
What counts as an overheating bedroom?
UK building studies commonly use 26°C measured in the bedroom overnight as the point where a room is treated as overheating. For comfortable sleep, The Sleep Charity suggests aiming lower, around 16 to 18°C.
How many UK homes overheat?
On modelling for the Climate Change Committee, around 55% of UK homes, about 15.7 million, would fail a night-time bedroom overheating test in the current climate. That rises to 92% by 2050 if no action is taken.
Is heat in the home actually dangerous?
It can be, for older and more vulnerable people in particular. England recorded 2,985 heat-associated deaths in 2022, the highest since monitoring began, in the year temperatures first passed 40°C. Most people will lose sleep rather than face danger, but the health risk is real at the extremes.
Sources
Overheating modelling: Arup, Addressing overheating risk in existing UK homes, for the Climate Change Committee (2022). Self-reported overheating: English Housing Survey 2020-21 (gov.uk). Heat mortality: UKHSA heat mortality monitoring report 2022. Temperature record: Met Office. Bedroom comfort range: The Sleep Charity.