Impact of Relative Humidity on Thermal Comfort in a Warm Environment

Relative humidity is an important environmental factor that could affect thermal comfort in a building. The influence of relative humidity on thermal comfort was studied in an environment chamber. Twenty subjects, ten males and ten females, were engaged in the study and were exposed to nine combinations of air temperature and relative humidity. Skin temperatures on different parts of the body were monitored, and their thermal sensation was evaluated by questionnaire while their thermal environments were measured during the chamber tests. These results were evaluated by statistical analyses which indicate that for higher temperature, relative humidity could have a significant effect on skin temperature and thermal sensation. Higher humidity could cause a negative effect on the subject’s thermal comfort. To avoid causing discomfort, the relative humidity limit should be taken into consideration and there should be a humidity limit specified by the appropriate building code for the acceptable air temperature range to allow an appropriate control of indoor environment.