The optimal temperature for a restful night's sleep

Some people sleep best in a warm bedroom; others can't drop off until the room is properly cool. But research is fairly settled: the optimal bedroom temperature for sleep sits between 15°C and 18°C — cooler than most people keep it. There are real, measurable benefits to this range, including deeper sleep, faster sleep onset, and even some surprising long-term health effects. Here's the science, and the practical tips for getting there without freezing.

1. Why a cool room helps you sleep
2. The benefits of a cooler bedroom
3. Practical tips for getting there
4. The role bedding plays
5. Finding your personal balance

Why a cool room helps you sleep

Your body's core temperature naturally drops as you fall asleep — this is a key part of how sleep is initiated. A cool bedroom supports this process; a warm one fights against it. If your room is too warm, your body has to work harder to lower its core temperature, which often shows up as restless turning, light sleep, and waking up feeling unrefreshed.

The reverse is also true: too cold and your body stays alert trying to maintain warmth. The 15–18°C range is the sweet spot for most adults.

The benefits of a cooler bedroom

• Deeper sleep — cooler temperatures promote slow-wave sleep, the most restorative phase
• Faster sleep onset — the natural temperature drop signals time to sleep to your brain
• Better melatonin production — melatonin, the sleep hormone, is suppressed by warmth
• Anti-aging effects — cooler nights are linked to higher production of certain regenerative hormones
• Slight metabolic boost — your body burns marginally more calories regulating temperature
• Lower energy bills — heating a bedroom less saves significantly on energy

Practical tips for getting there

• Crack a window — even slightly. Fresh air and a small temperature drop together work wonders
• Turn the heating down or off overnight — most thermostats can be programmed
• Block daytime heat — keep curtains drawn during the hottest part of the day in summer
• Cool down before bed — a slightly warm shower paradoxically helps, as your body cools rapidly afterwards
• Avoid heavy meals close to bedtime — digestion raises body temperature

The role bedding plays

Your bedding is half the temperature equation. The room can be 17°C, but if your bedding traps heat, your sleep environment isn't really 17°C anymore. This is where bamboo bedding earns its place: the fabric actively regulates temperature, releasing heat when you're warm and trapping it when you're cool. The sleep environment stays in the right zone even when room temperature shifts overnight.

For hot sleepers, a bamboo summer duvet combined with a cool room is often the difference between waking refreshed and waking sweaty. See why bamboo saves summer sleep.

Finding your personal balance

15–18°C is the research-backed range, but personal preference varies. Some people sleep best at the lower end; others find 19°C or 20°C still works well. The way to find your sweet spot: start at 17°C, adjust by a degree at a time, and pay attention to how rested you feel rather than how cosy the room feels at bedtime. The two aren't always the same.

For more on temperature and sleep, see our guide on heat and sleep.