Impact of overheated bedroom conditions on occupant thermal comfort and sleep quality: an experimental study

This study investigates the thermal comfort during sleep and sleep quality of occupants in overheated bedrooms in the UK and their association with environmental conditions in the bedroom. Ten healthy individuals with no sleep disorder participated in two stages of field work. In stage one, their baseline sleep was monitored for three nights in their own bedrooms during normal operating conditions during July to September 2022. In stage two, each participant slept for a further 3-night in a bedroom in which indoor temperature was controlled to stay constant at an elevated temperature of 30°C. Objective and subjective data on thermal sensation, thermal satisfaction, sleep quality, and sleep satisfaction were collected using environmental monitoring, skin temperature measurement, thermal comfort and sleep questionnaires, and actigraphy which is a validated method of objectively measuring sleep parameters. Results indicate a significant deterioration in sleep quality, sleep efficiency, and self-rated experience of thermal comfort during sleep in overheated conditions compared to the baseline. Further study should investigate the role of bed microclimate and low-energy personal cooling systems in controlling sleeping environments to mitigate the adverse effects of heat on sleep.