The best bedroom temperature for sleep

Why a cooler room, specifically

Falling asleep is not just a mental switch; it is a physiological one, and part of it is thermal. In the evening your body starts shedding heat from its core — that is why your hands and feet get warm, they are the radiators — and your core temperature drops by around a degree as you fall asleep and stays down through the night. A warm bedroom slows that drop, which is why a hot room makes you toss at the start of the night and wake in the small hours when your temperature is meant to be at its lowest.

A cooler room helps that natural cooling happen. The commonly cited range from sleep research is about 65 to 68°F for adults, a little warmer for infants. It is a range, not a magic number — your ideal depends on your bedding, your metabolism and what you wear — but if your room is in the mid-70s at night, that is a likely cause of the problem on its own.

The reason this page comes first

Here is the argument that runs through this whole site. Every passive cooling product — a sheet, a topper, a pillow, a blanket — works by moving heat from you to somewhere cooler, and the somewhere is the air in your room. If the room is 78°F, there is nowhere cooler for the heat to go, and the best percale sheets on earth cannot rescue the night. You would be trying to pour water uphill.

So the room is not one option among many; it is the precondition for all the others. It is also usually the cheapest thing to fix — much of it is free. That is why our what to fix first ladder starts here, before any purchase.

Getting the room there without a big AC bill

You do not need to refrigerate the house. Most of what works is cheap or free, and it is covered in detail on how to stay cool at night; the essentials:

• Move air. A fan does not lower the temperature, but moving air over skin speeds evaporation and feels several degrees cooler, and it keeps the humid layer from settling on you.
• Manage the day's heat. Close blinds against the sun during the day so the room does not bake, then open windows once the outside air drops below the inside air in the evening. Cross-ventilation beats a single open window.
• Lower the humidity. Sweat cools you only when it evaporates, and it cannot evaporate into already-damp air. In a humid climate a dehumidifier can do more for sleep than a couple of degrees off the thermostat.
• Target the person, not the building. If cooling the whole room is expensive, cool the bed: a fan aimed at you, or a powered bed cooling system, uses a fraction of the energy of air-conditioning a room.

Then, and only then, the bed

Once the room is in a sane range, the bedding starts to matter and the products on this site start to earn their keep. In the right order: breathable sheets, then a cooling topper or pillow, then, last and only if needed, the mattress. Fix the room first and you may find you need far less of the rest than you thought.