A sleeping adult produces about 17 liters of CO2 per hour. In a 35 m³ bedroom (a typical small-to-medium room) with the door closed and no mechanical ventilation, that production climbs steadily through the night. By 7 AM a one-person bedroom typically reads 1,200–1,500 ppm; a two-person bedroom 1,800–2,500 ppm; a child's room with the door shut tight can read higher still relative to room volume.
Lan et al. and Mishra et al. have documented that elevated bedroom CO2 correlates with measurably worse sleep architecture, more wakefulness, fewer slow-wave-sleep minutes, lower self-reported rest. Whether CO2 is the cause or a marker for poor ventilation (which carries other consequences) is still debated; either way, the intervention is the same.
The dashboard's overnight pattern detection identifies bedrooms by the characteristic shape: monotonic CO2 climb starting 1–2 hours after typical bedtime, peak just before typical wake time, sharp drop at door-opening. Humidity tracks alongside (sleeping adults exhale water vapor too). VOCs and PM stay flat.
Practical responses, ordered roughly by cost: leave the bedroom door open if pets and household allow (single largest intervention); crack a window an inch; run a quiet bedroom HRV/ERV (the ~$300 trickle-ventilation units do enough); install whole-house ventilation per ASHRAE 62.2.
