Quick answer: Most healthy adults do not need the heating on high all night. A bedroom of around 18°C suits both sleep and health: the NHS advises heating rooms you use, including your bedroom, to at least 18°C if you can, and sleep experts suggest a cool room of about 18 to 20°C. If you are over 65, have a health condition or are pregnant, keeping the bedroom from getting cold matters more.
Late October is when the UK heating debate starts in most homes. One person wants the radiators on overnight, the other wants the window open. The clocks go back at the end of this month, nights are getting longer and colder, and many of us are wondering what is best for sleep, health and the energy bill.
This guide covers the best bedroom temperature for sleep in a UK winter, when it makes sense to leave the heating on at night, and simple ways to stay warm in bed without overheating.
Should you sleep with the heating on?
It depends on how cold your bedroom gets and who you are. For most healthy adults, a bedroom that sits around 18°C is a good target. You may not need the heating on all night to keep it there, especially in a well-insulated home.
The NHS says rooms you regularly use, such as your living room and bedroom, should be at least 18°C if you can manage it (NHS). The UK Health Security Agency gives the same advice in its winter guidance, updated in April 2026 (UKHSA).
So the honest answer is: you do not need a hot bedroom, but you should not let it get very cold either. If your room drops well below 18°C overnight, a low heating setting or a timer that comes on before you wake is a sensible middle ground.
What is the best bedroom temperature for sleep?
According to the Sleep Foundation, the ideal bedroom temperature for most people is around 65 to 68°F, which is roughly 18 to 20°C, with about 18°C as a good single target (Sleep Foundation). Personal preference can shift this by a degree or two.
Why a cooler room helps you sleep
Your core body temperature is the temperature deep inside your body. It starts to fall about two hours before your usual bedtime, around the time your body releases melatonin, the hormone that helps you feel sleepy (Sleep Foundation). It keeps dropping through the night and reaches its lowest point in the early morning.
A cool room helps this natural drop. A hot, stuffy room works against it. That is one reason a heated bedroom at 23°C can leave you restless, even in January. This links closely to your body clock, which we cover in our guide on protecting your sleep when the clocks go back.
Is it bad to sleep in a hot bedroom?
For sleep quality, too warm is often a bigger problem than too cool. A review in the Journal of Physiological Anthropology found that in real-life conditions with bedding and nightwear, heat increased time spent awake and reduced deep sleep and REM sleep (Okamoto-Mizuno and Mizuno, 2012).
Newer research points the same way. A December 2025 study in BMC Medicine tracked 47 adults aged 65 and over in their own homes (O'Connor et al., 2025). When night-time bedroom temperatures rose above 24°C, people were more likely to show a higher heart rate and lower heart rate variability, a common marker of how well the body is recovering. The authors suggest keeping bedrooms at or below 24°C at night where possible.
That study took place during an Australian summer, not a British winter. But it is a useful reminder that turning the radiators up high in a small bedroom is not a recipe for restful sleep. If you want to get more of the deepest, most restoring stage of sleep, our guide on how to get more deep sleep has more tips.
Is it bad to sleep in a cold bedroom?
A cool bedroom is fine. A cold one can be a health risk for some people. The 2012 review found that with normal bedding, cold did not clearly change sleep stages, but it did change how the heart was working during sleep (Okamoto-Mizuno and Mizuno, 2012). The authors also said that bedding and clothing are key for good sleep in the cold.
The NHS lists groups who are more at risk from cold weather (NHS):
- Adults aged 65 and over
- Babies and children under 5
- People on a low income who cannot afford heating
- People with a long-term health condition or a mental health condition
- Disabled people
- Pregnant women
If you or someone you live with is in one of these groups, keeping the bedroom at 18°C or above is more important than shaving a little off the bill. The NHS also advises keeping bedroom windows closed at night in cold weather. If you are worried about how the cold affects a health condition, speak to your GP or pharmacist.
Everyone is a little different
A small study published in Innovation in Aging in December 2025 followed 13 adults aged 65 and over across 538 nights at home (Lee et al., 2025). For 4 of the 11 people with enough data, sleep efficiency changed with bedroom temperature. For the rest, it did not. The authors call these early findings, but they suggest the "perfect" temperature is partly personal. Try a few settings and notice how you feel.
What temperature should a baby's room be at night?
Babies need extra care. The Lullaby Trust recommends a room temperature of 16 to 20°C for safer sleep (The Lullaby Trust). It says it is rarely necessary to keep the heating on all night, and if you do, to keep it low and no higher than 20°C. It also advises keeping the cot away from radiators and heaters, and says babies do not need hats indoors.
How to stay warm in bed without overheating the room
You can keep the room cool and still feel cosy. These simple steps help.
- Use a thermostat or timer. Let the room cool a little overnight, then have the heating come on before you get up. This keeps the room from getting very cold without heating it all night.
- Layer your bedding. Layers you can add or kick off work better than one very heavy duvet. Research shows bedding plays a big role in sleeping well in the cold.
- Warm your feet. In a small 2018 study of six young men sleeping in a 23°C room, wearing warming bed socks helped them fall asleep about 7.5 minutes faster and sleep about 32 minutes longer (Ko and Lee, 2018). It is a tiny study, but warm feet help your body release heat, which supports the natural drop in core temperature.
- Use electric blankets safely. Greater Manchester Fire and Rescue advises unplugging an electric blanket before getting into bed unless it has a thermostat for safe all-night use, never using one with a hot water bottle, checking it often for damage and replacing it after around ten years (GMFRS).
- Close curtains at dusk. This helps keep heat in as the evenings draw in.
- Keep a steady routine. Regular bed and wake times matter as much as temperature. Our sleep hygiene tips cover the basics.
Does central heating cause damp or dry air in the bedroom?
Both can happen, in different ways. Cold bedrooms are more prone to condensation, because moist air settles on cold windows and walls. The Centre for Sustainable Energy, which the NHS links to for damp advice, notes that even breathing adds moisture to the air, and that damp and mould are bad for your health (CSE).
Its advice is to heat your home enough to keep it dry in colder months, open trickle vents, avoid drying clothes in the bedroom where you can, and aim for indoor humidity between 40% and 60%. A cheap hygrometer can show you where your room sits. Mould risk rises above 60%.
On the other side, some people find a warm, heated bedroom leaves them waking with a dry mouth or throat. Breathing through your mouth at night can add to this. Our guide on mouth breathing during sleep explains why.
Where DELIM fits in
The right bedroom temperature is about comfort, health and safety first. No product replaces a sensible thermostat and good bedding. But if you often wake with a dry mouth on winter nights, it may be worth looking at how you breathe while you sleep.
Some people use gentle mouth tape for sleep to encourage nasal breathing, and DELIM mouth tape is one option. It does not treat any condition. If you have a blocked nose, a cold, breathing problems or sleep apnoea, speak to your GP before trying mouth tape.
Frequently asked questions
Should you sleep with the heating on in winter?
Most healthy adults do not need the heating on all night. Aim for a bedroom of around 18°C. If your room gets much colder than that, or you are over 65, pregnant or have a health condition, a low setting or a timer is a sensible choice.
What temperature should my bedroom be at night in the UK?
The NHS advises at least 18°C in rooms you use regularly, including the bedroom. Sleep experts suggest roughly 18 to 20°C for good sleep, so around 18°C works well for most adults.
Is 16 degrees too cold to sleep?
For a healthy adult with warm bedding, 16°C may feel fine. But it is below the 18°C the NHS advises, so it is not ideal for older people or anyone with a health condition. For babies, the Lullaby Trust says 16 to 20°C is the right range.
Is it cheaper to leave the heating on low overnight?
Costs depend on your home, insulation and heating system. A simple approach is to use a thermostat and timer so the bedroom does not drop too low, rather than heating it high all night.
Does sleeping in a warm room affect sleep quality?
Yes, it can. Research links a hot bedroom with more time awake and less deep and REM sleep. A 2025 study in older adults also linked bedrooms above 24°C with a higher night-time heart rate.
The bottom line
You do not need to sleep with the heating on high, but you should not let your bedroom get very cold either. Around 18°C is the sweet spot for most people, with layered bedding and warm feet doing the rest. As winter sets in, take a look at our guide on how to improve sleep quality for more simple changes.
This post is for information only and is not medical advice. If you have a health condition, or are worried about how the cold affects you or someone you care for, please speak to your GP or pharmacist.
Written by the DELIM team, a UK sleep wellness brand.
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