Sleep is recognized as a phenomenon controlled by the circadian rhythms. It is generally believed that sleep is important for stabilizing the energy, supporting healthy immune system of human body, besides, it is beneficial for brain plasticity and mental health [1,2]. The thermal environment while sleeping are perceived by human beings both cutaneously stimulated and emotionally provoked. A preferable thermal environment should be within the thermal regulation range of human body and evoke the best thermal sensation. With regard to the thermal environment for sleeping during night
Recently, air-conditioner use has become a heat stroke countermeasure. Studies of air-conditioner use and sleep quality have been conducted. Kubo et al.[1] conducted a questionnaire survey designed to evaluate thermal environment changes from airconditioner use during sleep. Results show that air-conditioner use during sleep affects thermal comfort when waking up. Ishimaru et al.[2] surveyed thermal environments during sleep. They reported that air-conditioner use causes waking up during sleep by a timer function.
Sakane et al.[3] administered a questionnaire survey to Osaka City apartment residents in September 2012 to assess parameters of living environments, air-conditioner use, and sleep quality. Results revealed that the sleep quality of full time workers is affected by ‘residential heating and cooling performance’, ‘solar heat from windows’,and the air-conditioner use frequency during the day