The room temperature directly affects sleep quality, comfort, and even health, especially in young children. If the room is too warm, it makes it harder to fall asleep and causes sweating; if it is too cold, it can cause night-time awakenings. Knowing what temperature to aim for in a bedroom, depending on age and season, helps you sleep better without overheating your home.
What is the ideal bedroom temperature for a good night's sleep?
For adults, sleep specialists recommend keeping the bedroom fairly cool, between 16 and 18°C. The ideal temperature is around 18°C, a level that promotes the production of melatonin, the hormone that prepares the body for sleep.
A room that is too warm disrupts falling asleep and leads to more awakenings, while air that is too cold makes the body tense. The right guideline is therefore a temperate bedroom, neither stuffy nor freezing, where body heat can naturally decrease at bedtime.
How bedroom temperature affects sleep
The body naturally lowers its internal temperature to fall asleep, then keeps it low throughout the night. A cool bedroom supports this process, while an overheated room works against it and fragments sleep.
Cooler temperatures also stimulate melatonin secretion, which regulates the body clock. Just a few extra degrees can lengthen the time it takes to fall asleep and increase micro-awakenings, often without us even realizing it.
What temperature is suitable for a baby's or newborn's bedroom?
Infants require more attention because they are not good at regulating their body temperature. According to recommendations from the French Ministry of Health and ADEME, a baby's bedroom should be between 18 and 20°C, or around 19°C on average, both day and night.
This range applies in winter as well as summer. It is best never to go below 16°C or above 22°C, as excessive heat increases the risk of heatstroke and sudden unexpected infant death. Also pay attention to the humidity level, ideally between 40 and 60%.
The right temperature according to the child's age
The 18 to 20°C range remains suitable from the newborn stage through the age of 2 or 3. What changes with age is not the room temperature but the clothing: at 6 months, 1 year, or 2 years, simply adjust the thickness of the pajamas and sleep sack according to how the child feels.
An older child can then sleep in a slightly cooler room, closer to the temperature suitable for an adult. If you remain unsure about your baby's comfort, a pediatrician's advice is still the best reference.
What temperature should a bedroom be in winter?
In winter, the temptation to overheat the room is strong, but a bedroom does not need to be as warm as a living room. ADEME recommends around 17°C in bedrooms and 19°C in living areas, a setting that supports sleep while limiting energy bills.
Set the radiator to around 18 or 19°C in a child's bedroom, and place the bed a safe distance from the heat source. A thermostat, especially a connected one, helps maintain a stable temperature and control it remotely without waking anyone. Finally, remember to air the room for about ten minutes every day, even when it is cold, to renew the air and prevent it from becoming too dry.
Heating accounts for a significant share of a household's energy costs. Lowering the bedroom temperature by one or two degrees at night can often save money without harming sleep quality.
What temperature should a bedroom be in summer?
In summer, the challenge is reversed: you need to keep the heat out. Closing shutters and curtains during the hottest hours blocks much of the outdoor heat and keeps the room cooler.
Air the room early in the morning or late in the evening, when the outdoor air is cooler. A fan pointed away from the bed is often sufficient; if you use air conditioning, avoid directing the airflow onto the bed, especially when a baby is sleeping. As for clothing,
A lightweight bodysuit or thin pajamas can replace winter layers. During heat waves, the main thing is to ensure that the room does not remain above 22°C for a baby.
How can you tell if a baby is too hot or too cold?
An infant's hands and feet are often cool without this indicating a problem. To truly assess their comfort, touch the nape of their neck or upper back instead: warm, dry skin indicates a comfortable temperature.
A damp neck, flushed cheeks, and rapid breathing indicate excessive heat. Conversely, a noticeably cold neck suggests that you need to warm the room or add a layer. If concerning signs appear despite a suitable temperature, contact a healthcare professional.
When should you be concerned about a child?
Most discomfort can be corrected by adjusting the room or the child's clothing. However, some signs require extra vigilance: heavy sweating, very hot skin, or, conversely, a cold body accompanied by unusual restlessness.
In the event of a fever, difficulty breathing, or behavior that causes concern, the bedroom temperature becomes secondary: it is best to consult a doctor or pediatrician promptly. These guidelines do not replace medical advice.
TOG ratings for sleep sacks: how to adapt them
TOG measures a sleep sack's ability to retain heat: the higher the rating, the warmer the model. Choose a lightweight TOG of around 1 for summer and a thicker model rated 2 to 2.5 for winter.
The dressing rule is simple: use one more layer than an adult would wear to sleep in the same room. A sleep sack is a better alternative to a duvet or blanket, which are not recommended in a baby's bed, and hats have no place indoors at night because the head helps release heat.
How to measure and maintain the right temperature
You can only regulate what you measure. A room thermometer, ideally combined with a hygrometer, lets you check the room temperature and humidity level at a glance.
A few simple steps can help maintain a stable environment.
- Place the thermometer near the bed, away from the radiator and window.
- Keep the heating at a constant level rather than making large adjustments.
- Air the room briefly every day to renew the air without cooling the room for an extended period.
- Keep the bed away from direct heat sources and drafts.
Minimum and maximum temperature in a home
A decent home should be capable of being heated to a normal temperature, generally around 18 to 19°C. There is no strict legal maximum for a private home, but maintaining moderate heat is preferable for both health and energy consumption.
Older people are particularly sensitive to a room that is too warm at night, which calls for caution during heat waves. In all cases, aiming for the right temperature rather than excessive heat benefits both sleep and your budget.
The role of bed linen in thermal comfort
Room temperature is not everything: bed linen adjusts the sensation of warmth or coolness close to the body. A breathable fabric wicks away moisture and stabilizes comfort throughout the night.
In summer, a cool weave such as cotton percale keeps the bed light and dry. In winter, cotton sateen provides a softer, more enveloping feel, while washed linen, naturally temperature-regulating, remains comfortable in every season. Choosing bed linen according to the time of year ideally complements the bedroom temperature setting.