"Comfortable" temperature is more specific than it sounds. ASHRAE Standard 55 defines a comfort zone using six variables (air temperature, radiant temperature, humidity, air speed, metabolic rate, and clothing), and the resulting envelope runs roughly 20 to 25 °C (68 to 77 °F) for typical office activity in normal clothes.
Sleep is a special case. The bedroom comfort zone is meaningfully cooler. Lan et al. and others put the sleep optimum at 18 to 20 °C (64 to 68 °F). The body needs to dump heat to fall asleep, and a warm room delays that. Bedrooms that run warmer than 22 °C reliably produce more fragmented sleep.
Workplace effects are well-documented. Productivity peaks around 22 °C and falls in both directions; offices that run cold (under 20 °C) show measurably more typo rates and slower task completion. OSHA heat-exposure rules apply at the high end for safety.
The sensor reads temperature from the Sensirion SEN66 (factory-calibrated to ±0.5 °C), with the Bosch BMP390L's internal die-temperature available as a sanity cross-check.
References
- ASHRAE Standard 55 - Thermal Environmental Conditions www.ashrae.org
- CDC / NIOSH - Temperature in indoor environments www.cdc.gov
- OSHA - Heat exposure www.osha.gov
- Lan et al. - Bedroom temperature and sleep doi.org
