The Impact of Bedroom Air Quality on Sleep and Health

The bedroom, where individuals spend a significant portion of their lives, might be causing harm according to sleep and air-quality experts. In 2015, researchers observed airtight, naturally ventilated homes during a Scottish winter. They found that in over 80% of homes, CO2 levels remained above safe limits throughout the night. Despite this, more than 90% of residents believed the air quality in their bedrooms was satisfactory.

Experts in 2026 have highlighted that the issue of trapped air is becoming a summer problem too. Heatwaves are testing homes not built for extreme heat, while global temperatures rise. According to Devjoy Dev, a biomedical engineer who researched sleep circuitry neuromodulation at New York University, “Global warming causes drastic and abrupt shifts in temperatures.” This situation has led to sudden heat waves across Europe, lacking sufficient AC infrastructure. Dev, with Harvard Medical School training, points out how bedroom elements like curtains and carpets trap heat and moisture overnight.

Dr. Ayesha Bryant from Alpas Wellness, Maryland, mentioned that bedrooms experience average nighttime CO2 levels exceeding about 1,520 parts per million (ppm). High CO2 levels stand as indicators of stale air, measured in ppm. “A room can have a comfortable temperature while the air from exhaling humans and moisture build-up continuously occur,” Bryant said, highlighting that CO2 and heat can degrade sleep quality long before noticeable issues arise.

Effects of High Nighttime Temperatures

Experts explain that the real problem lies not with the room, but what ceases happening once occupants fall asleep. While awake, individuals open windows when air seems stale or close them feeling cold—actions that stop overnight, permitting CO2 and moisture buildup. Bryant clarified that CO2 isn’t dangerous at such levels but signifies poor air exchange tied to lesser sleep and next-day performance. A 2022 study on 40 Danish bedrooms revealed cognitive decline starting once CO2 hit 1,800 ppm. Sleep quality worsened earlier, potentially causing health problems over time.

Dev stressed the importance of understanding sleep environments and their ‘zeitgebers’—environmental factors like light and schedules affecting the circadian rhythm. “Controlling these in your bedroom is vital for quality sleep,” Dev remarked, noting their degradation when CO2 and moisture levels rise.

Addressing the Air Quality Issue

Poor airflow, closed doors, inadequate insulation, and west-facing windows contribute to bedroom heat entrapment. Insights from June’s Amerisleep study reported 52% of Americans identify as hot sleepers, with 94% experiencing wake-ups weekly due to it, contrasting 58% of cold sleepers. Women had double the likelihood compared to men of waking thrice weekly from heat. The ideal bedroom temperature averages between 65–67°F; however, most report actual temps of 68–70°F.

Bryant urges keeping trickle vents clear and airing rooms when external temperatures allow. The German “Lüften” practice, trending among Gen Z as “house burping,” involves opening windows fully for 10-15 minutes each morning to expel stale humid air. Dehumidifiers, priced around £90 to £300, help maintain recommended 60% humidity. For persistently hot conditions, repairing HVAC systems or installing air conditioning is advised, addressing any mold or condensation at its source rather than simple surface cleaning.

Fan, X., et al. (2022). A field intervention study of the effects of window and door opening on bedroom IAQ, sleep quality, and next-day cognitive performance. Building and Environment. https://doi.org/10.1016/j.buildenv.2022.109630. Sharpe, T., et al. (2015). Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK. International Journal of Environmental Research and Public Health. https://doi.org/10.3390/ijerph120708480.