What temperature should your baby's room be once the heating goes on?

5 min read

Quick answer: Keep your baby's room between 16 and 20°C, which the NHS says is comfortable and safe for sleeping babies. At that temperature a sleepsuit and a 2.5 tog sleeping bag usually works. To check how warm your baby is, feel their chest or the back of their neck, not their hands.

What parents need to know

Once the heating comes on, a nursery can climb past 20°C without you noticing, especially if the cot is near a radiator. A room thermometer by the cot gives you a reading instead of a guess, and the NHS recommends using one.

When the house turns cold, it's natural to want to add layers. The NHS is clear that babies are better off cooler than too hot, because overheating raises the risk of sudden infant death syndrome (SIDS). This applies to every sleep, day or night, up to 12 months.

Which sleeping bag tog for which room temperature

Sleeping bags have a tog rating, which tells you how warm they are. The NHS lists these ranges for commercial sleeping bags. Use them as a starting point and check the manufacturer's label too.

A sleeping bag needs to fit well around the shoulders so your baby's head can't slip down inside. Don't put any other bedding on top of it.

Room temperature	Sleeping bag tog	Typical use
16 to 20°C	2.5 tog	All year, standard rooms
20 to 24°C	1.0 tog	Warmer weather and warmer rooms
24 to 27°C	0.5 tog	Hot weather

What your baby wears underneath

In winter, the NHS says a sleepsuit plus a sleeping bag, or a sheet and/or blanket, should be fine. Change the clothing under the bag to suit the tog and the room temperature.

If the room is cooler than usual

If your baby is in a sleeping bag and seems cold, the NHS advises adding one more layer of clothing, not extra blankets. A thermometer reading below 16°C means the room needs warming.

If the room runs warm

Use a lower-tog bag and fewer layers. On the warmest nights, a vest or just a nappy is enough.

If you use blankets instead of a sleeping bag

Choose lightweight cellular cotton blankets, which keep your baby warm and still let air through. Avoid thick, fleecy or padded ones.

Lay your baby on their back in the feet-to-foot position, with their feet at the foot of the cot. Tuck the blanket in firmly no higher than the shoulders. Don't double it over: a folded blanket counts as two.

What stays out of the cot, even in winter

Soft items around a baby, especially near the head, can cause overheating and raise the risk of SIDS. The NHS advises keeping the cot clear of anything that could cover your baby's face or head.

Take off hats and extra clothing as soon as you come indoors, even if it wakes your baby.

No hats indoors or in the cot
No duvets, pillows, cot bumpers or loose blankets
No sleeping pods, nests or anything else used to keep your baby in place
No hot water bottle or electric blanket
No cot positioned next to a radiator, heater or fire, or in direct sunlight

How to check if your baby is too hot

Small babies aren't good at controlling their own temperature. They can overheat from too much clothing, too much bedding or a room that's too warm.

Feel the chest or neck. Put your hand on your baby's chest or the back of their neck. Cool hands and feet are normal and don't tell you much
Look for sweating. Damp hair, a sweaty neck or a hot tummy means they're too warm
Remove a layer. Take off one or more layers of clothing or bedding, then check again a little later
Check the thermometer. If the room is above 20°C, turn the heating down or move to a lower-tog bag

When to get help

Get an urgent GP appointment or contact 111 if you're worried about your baby or think they might be ill.

Call 999 if your baby stops breathing, won't wake up, is struggling to breathe, is stiff, shaking or jerking, or is limp, floppy or not responding like they normally do. Also call if their lips, tongue, face or skin suddenly turn pale, blue or grey. On black or brown skin, this may be easier to see on the palms of the hands or the soles of the feet.

Practical checklist

Put a room thermometer near the cot and aim for 16 to 20°C
Use a 2.5 tog sleeping bag over a sleepsuit for a standard room
If your baby is in a sleeping bag and feels cold, add a layer of clothing, not extra blankets
Move the cot away from radiators and heaters
Take off hats and outdoor layers as soon as you're inside
Check warmth at the chest or back of the neck

Frequently asked questions

Does a baby with a fever need extra layers in winter?

Usually not. The NHS says that, even in winter, most babies who are unwell or feverish don't need extra clothes. Contact 111 or your GP if you're worried. NHS guidance

What about naps in a warm car?

Take off hats and extra layers as soon as you get into a warm car, bus or train. It's fine for your baby to fall asleep in the car seat while you're travelling, but take them out once you arrive. NHS guidance

Can the mattress affect how warm my baby gets?

Yes. A mattress that isn't firm enough makes it harder for a baby to lose heat. Your baby's head shouldn't sink in by more than a few millimetres. NHS guidance

My baby was premature. Does any of this change?

Follow the same safer sleep advice, but for a year from your baby's due date rather than their birth date. NHS guidance

Sources & further reading

nhs.uk: Safer sleep
Source checked 2026-10-02
nhs.uk: How to dress a newborn baby
Source checked 2026-10-02
nhs.uk: Sudden infant death syndrome (SIDS)
Source checked 2026-10-02

General information, not individual medical advice. Speak to your GP, midwife or health visitor about your baby’s needs.