The Real-World Bedroom Temperature That Sleeps Best

Rather than testing sleep in a laboratory, this team fitted 50 community-dwelling older adults with wearable sleep monitors and home environmental sensors and simply watched what happened over 18 months, gathering close to 11,000 nights of real bedroom temperature and sleep data. The clearest finding was a comfort band: sleep efficiency, duration and restlessness were all best within a bedroom temperature range of roughly 20 to 25°C, and got measurably worse as the room moved towards 30°C, with sleep efficiency dropping 5 to 10 percent at the higher end.

What makes this study distinctive is also its main caveat: it captured real homes rather than a controlled sleep lab, so it reflects how people actually sleep, but it also found substantial variation between individuals, some slept best cooler, some slightly warmer, and that personal range shifted over time rather than staying fixed. The sample was limited to older adults, so the exact numbers may not transfer directly to younger sleepers, but the core message travels well: a consistently cool, stable bedroom is one of the simplest environmental levers available for better sleep, and the ideal temperature is worth finding for yourself rather than assuming.