A Survey on Nocturnal Air Conditioner Adjustment Behavior and Subjective Sleep Quality in Summer

Sleep is a critical physiological process for the mental and physiological restoration of people. The air conditioning usually serves as a common approach to maintain or improve sleep quality. However, available data are still limited regarding the actual sleep quality under different air conditioning modes, which leads to insufficient evidence to support the optimization of the temperature control strategies of air conditioners. To address this gap, an online questionnaire survey was carried out to identify the adjustments of air conditioners during nocturnal sleep, as well as the subjective sleep quality of residents in the summer. A total of 571 valid responses were collected from participants across various age groups, genders, and climatic regions in China through the online surveys that considered several aspects of sleep and air conditioner usage. Pearson’s Chi-square test was used to detect the differences between items in surveys. The results indicated that 74.6% of respondents used air conditioners to regulate their sleep environments in summer, with a preferred temperature of approximately 26 °C. Gender difference had a limited contribution to the adjusting behaviors of air conditioners (χ2 = 3.83, p = 0.281), while age played a significant role (χ2 = 20.06, p = 0.018). On the contrary, sleep-related adjusting behaviors of the air conditioner were more influenced by subjective factors such as concerns about being awakened by cold or heat. Nonetheless, over 50% of respondents reported experiencing thermal disturbances during sleep, including awakenings by either cold or heat, regardless of the adjustments (χ2 = 20.3, p = 0.002). Furthermore, 68.7% of respondents reported their preference for dynamic temperature adjustments during sleep. Findings revealed that the age and subjective aspects were critical for the adjusting behaviors of air conditioners during sleep, and the dynamic air conditioning control was preferred more by users. This study provided empirical evidence to support the optimization of air conditioning modes and the development of adaptive, dynamical sleeping air conditioning systems.