Appropriate indoor operative temperature and bedding micro climate temperature that satisfies the requirements of sleep thermal comfort

The thermal comfort theories in workplaces during the day are well studied, but research on the thermal comfort of sleeping environments at night is limited. The bedding micro climate has a greater impact on thermal comfort for subjects with bedding covers during the sleeping period compared with the indoor thermal environment. To investigate the effect of the bedding micro climate on sleep quality and thermal comfort during sleep under different indoor operative temperature and to obtain the appropriate indoor operative temperature and bedding micro climate temperature that satisfies sleep thermal comfort, the mean skin temperature (MST) and bedding temperature (BT) of each subject during the sleep period were measured in this experiment. The thermal sensation vote (TSV) and thermal comfort vote (TCV) of pre-sleep, post-sleep and bed micro climate were investigated simultaneously. The results indicated that the thermal neutral temperature of pre-sleep and post-sleep TSV was 18.3 °C. The subjects' comfortable temperature ranges of pre-sleep and post-sleep TCV were 15.8 °C–20.6 °C and 15.8–18.3 °C, respectively. The operative temperature of 15.8 °C was thermally neutral and comfortable during sleep. A BT of 30 °C–30.8 °C was considered a comfortable temperature range during the sleep period, and the corresponding indoor operative temperature was 14.5 °C–17.5 °C. The subjects' TSV of bedding micro climate was neutral when the mean bedding temperature (MBT) was 30.4 °C.