Human response to the indoor environment under fluctuating temperature

The effect on humans of a 6-hour long exposure to cyclic fluctuating air temperature was examined. The tested fluctuating pattern consisted of a gradual sweep-up +2.0°C over 40 minutes and a rather abrupt sweep-down –2.0°C over 20 minutes, within the temperature ranges of 26–28°C and 27–29°C. The experiment on cyclic fluctuating air temperature demonstrates that the thermal dissatisfaction rate for cyclic fluctuating air temperature control between 26°C–28°C is lower than that for constant air temperature control at 26°C, while consuming less energy. Moreover, occupant stress levels measured by salivary alpha-amylase, and subjective fatigue levels under cyclic fluctuating air temperature show that similar or even lower distinct results can be achieved with fluctuating air temperature control compared with constant air temperature control.