Bedroom Nighttime Temperature, Humidity and Sleep Duration in Singapore Homes

Abstract: Warming nights are increasingly recognized as a determinant of sleep loss, yet most evidence relies on outdoor temperature proxies that may not reflect the indoor bedroom exposures that occupants can modify. We assessed how night-to-night variation in bedroom thermal environments relates to total sleep time in a longitudinal study of working adults in Singapore, using data from 33 participants over 1,460 nights (mean 44 nights/participant). Bedrooms were found to be consistently warm and humid, but within-person associations between bedroom temperature, humidity, Heat Index and nightly total sleep time were small and imprecise across model specifications. Preliminary analyses assessing non-linearity did not support a single indoor ‘warm-night’ threshold. This suggests that actionable indoor guidance for sleep may need to consider both thermal conditions and night-to-night behavioral responses (e.g., cooling and ventilation practices), rather than temperature alone, pending confirmation in the full dataset.

Full text available at: ResearchGate

Recommended citation: Renard, M., Miller, C., Frei, M., Chua, Y. X., Tan, P. M. S., Kyaw, G. M. M., Zhang, W., Seah, J. X. T., Fan, X., Zhang, H., Parkinson, T., Lo, J. C.-Y., Lee, J. K. W., & Schiavon, S. (2026). Bedroom Nighttime Temperature, Humidity and Sleep Duration in Singapore Homes. Indoor Air 2026.