To sleep warm in winter, keep the room cool but not cold and warm the bed instead. Cold feet at midnight are miserable, and most of the fixes start with the bed rather than the boiler. Turning up the heating is tempting, but you don't need a hot bedroom to feel snug under the covers.
Sleeping warm in brief
Warm the bed, not the room, with another layer or a warmer duvet. The Sleep Charity puts the ideal bedroom at around 16 to 18C, and says about 12C makes dropping off harder. A warm bath or shower 1 to 2 hours before bed can help you fall asleep sooner, and bed socks help cold feet. Unplug an electric blanket before you get in unless it has a thermostat control for safe all-night use, and never use it with a hot water bottle.
A cool bedroom is normal, but about 12C is too cold to drop off
The Sleep Charity says body heat peaks in the late afternoon, then drops in the evening to prepare you for sleep. It puts the ideal bedroom temperature around 16 to 18C: over 24C is likely to make you restless, while about 12C makes it hard to drop off.1 Young children and older people may need it slightly warmer, so a room thermometer is worth having.
I'd aim for around 18C, with a warm bed in a cool room.
What does your bedroom thermometer say?
- Around 12C makes it hard to drop off, says the Sleep Charity. Warm the room a little, and add a layer to the bed.
- Just under the 16 to 18C the Sleep Charity calls ideal. An extra layer or a warmer duvet should do it.
- Right in the 16 to 18C the Sleep Charity calls ideal. Warm the bed and leave the room alone.
- Warmer than the 16 to 18C ideal. Drop a layer, or turn the heating down a touch. Young children and older people may need it warmer.
- Over 24C is likely to make you restless, says the Sleep Charity. Cool the room down.
Warm the bed, not the room
An electric blanket on a timer before bed, unplugged when you get in, warms the bed without heating the room. Adjust the tog of your duvet before reaching for the thermostat. I like a heavy tog all year because the weight helps me settle, and I can stick a leg out to cool down. I wouldn't push that on everyone, though. In my house, the hot water bottle is the cat's rival.
Add a layer to the bed before you turn up the heating
The Sleep Charity says an extra layer of sheets or blankets will make you more comfortable when it's cold. Heating the whole house to warm one bed is an expensive way round, to my mind. I sleep naked, always, but that's about temperature rather than virtue, and once the duvet is right the pyjamas are optional.
Warm the bed, not the room: an extra blanket on the duvet comes before turning up the heating.
A warm bath 1 to 2 hours before bed can help you drop off sooner
Haghayegh and colleagues' review pooled studies of warm showers or baths before bed. Water at 40 to 42.5C was linked with better self-rated sleep and sleep efficiency.2 Taken 1 to 2 hours before bed, for as little as 10 minutes, it was also linked with falling asleep sooner. The authors put this down to your body cooling afterwards as heat leaves through your hands and feet. It's a review of 13 studies, and the authors say more research is needed on timing and duration, so don't get too fixated on the clock.
Dry off fully before you get into bed, especially if you use an electric blanket, as Electrical Safety First advises.5
In the bath studies, when did a warm bath or shower help people fall asleep sooner?
- Straight before getting into bed
- 1 to 2 hours before bed
- First thing in the morning
Timed 1 to 2 hours before bed, even 10 minutes of warm water was linked with falling asleep sooner. The cool-down afterwards seems to be what helps.
Bed socks help cold feet, and a hot water bottle needs a cover
Raymann and colleagues found that adults wearing warm or neutral bed socks after lights off fell asleep faster, linked to a rise in foot temperature.3 These were small lab studies. The effect was smaller in older people, and none of the foot warming methods helped older people with insomnia. Treat socks as a simple comfort measure, and don't expect them to fix insomnia.
Bed socks are a simple comfort for cold feet. Always use a cover on a hot water bottle, and never fill it with boiling water.
NHS Mid and South Essex's advice on preventing burns is to never fill a hot water bottle with boiling water, always use a protective cover, and replace it every two years.4 Follow that replacement interval even if you're tempted to keep using the same bottle for another winter.
Use an electric blanket safely
The London Fire Brigade advice is worth following to the letter, because an old or misused electric blanket is a fire risk.6
Using an electric blanket safely:
- unplug it before you get into bed, unless it has a thermostat control for safe all-night use
- never use a hot water bottle at the same time
- check it regularly for wear and tear, and replace it at least every 10 years
- don't buy one second-hand
Never use an electric blanket if you have an air flow pressure relief mattress or use emollient creams. (London Fire Brigade)
Electrical Safety First's checks give you specific signs to look for when checking your blanket's condition:
- no scorch marks or discolouring
- no fraying or worn fabric
- no wires showing through
- the cord and connector are undamaged
- the control doesn't buzz or smell when it's on
If any of these checks fails, replace the blanket. Use it flat, never folded, rucked or pinned in place.
Questions people ask about sleeping warm
Yes, on the coldest nights, as long as the bedroom stays on the cool side. A room that's too cold makes it hard to drop off and one that's too warm makes you restless, so keep the heating low and check with a thermometer. Older people and young children may need the room a little warmer. My first choice is still to warm the bed before the room.
For many people, yes, and to my mind a warmer duvet does the job better than heating the room. The Sleep Charity's advice for cold nights is an extra layer of sheets or blankets, and a heavier duvet works the same way. If you overdo it, a leg out from under the covers cools you down quickly. Try the bedding you already have before buying anything new.
No, the London Fire Brigade says never use a hot water bottle at the same time as an electric blanket. Pick one way to warm your bed, even on a very cold night. Never fill a hot water bottle with boiling water. Always use a protective cover, and replace the hot water bottle every two years.
