How Bedroom Air Quality Impacts Sleep and Health

The room where individuals spend approximately one-third of their lives may also be the one causing them the most harm, according to experts in sleep and air quality. A study conducted in 2015 focused on airtight, naturally ventilated homes in Scotland during winter, revealing that in over 80% of homes, CO2 levels exceeded safe limits all night. Despite this, more than 90% of residents believed their bedroom air was satisfactory. Experts reviewing these findings in 2026 highlight the emergence of a similar issue as a summer risk, due to heatwaves affecting homes not designed for higher temperatures, while global warming continues to rise.

“Global warming causes drastic and abrupt shifts in temperatures,” stated Devjoy Dev, a biomedical engineer who has studied the neuromodulation of sleep circuits at New York University. “This has led to extreme heat waves across Europe, where air conditioning infrastructure is often lacking.” Dev, who trained at Harvard Medical School, noted that bedroom fabrics such as curtains and carpets trap heat and moisture overnight, exacerbating the issue.

Dr. Ayesha Bryant, a clinical adviser at Alpas Wellness in Maryland, explained that research found average nighttime carbon dioxide levels in bedrooms to be over 1,520 parts per million (ppm). Elevated CO2 levels indicate poor air quality, which negatively impacts sleep even before symptoms become noticeable. Yet, how does continued exposure to trapped air in bedrooms affect health over time?

A Room Without Temperature Regulation

Experts suggest that the underlying problem is not solely the room itself, but the lack of air circulation once individuals fall asleep. While awake, people tend to open a window if the air feels stale or close it when it gets cold. During sleep, this instinctual regulation stops, allowing CO2 and moisture to accumulate. Dr. Bryant noted that while CO2 at these concentrations is not directly harmful, it signifies inadequate air exchange, contributing to reduced sleep quality and impaired daytime performance.

A 2022 study on 40 Danish bedrooms demonstrated that cognitive function diminishes when CO2 levels surpass 1,800 ppm, with sleep quality deteriorating well before these levels. Over time, this decline can lead to several health issues.

“It is essential to consider the sleep environment and its ‘zeitgebers’,” Dev emphasized, referencing environmental cues like light, food schedules, and temperature that regulate the body’s circadian rhythm. “Managing these factors in your bedroom is crucial for achieving quality sleep, as they degrade when CO2 and moisture levels rise.”

Improving Air Quality

Poor air circulation, closed doors, insufficient insulation, and west-facing windows all contribute to trapped heat in bedrooms. Amerisleep research from June indicates that 52% of Americans identify as hot sleepers, with 94% of them waking up weekly due to heat. In contrast, cold sleepers experience similar disturbances 58% of the time. Women are twice as likely as men to wake from heat three or more times a week.

While many consider 65–67°F the ideal bedroom temperature, the actual range often sits between 68–70°F. Dr. Bryant suggests keeping trickle vents clear and ventilating rooms when outdoor conditions allow. The German practice of “Lüften,” recently gaining popularity on social media as “house burping,” involves fully opening windows for 10-15 minutes each morning to clear stale, humid air. Dehumidifiers, typically priced between £90 to £300, can maintain humidity near the recommended 60%.

In persistently warm rooms, upgrading HVAC systems or installing dedicated air conditioning is advisable. Mold and condensation issues need addressing at the source rather than merely wiping away.

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.

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.