Use of mean skin temperature in evaluation of individual thermal comfort for a person in a sleeping posture under steady thermal environment

A new model to evaluate individual thermal comfort using mean skin temperature was proposed. Twenty-two subjects’ local skin temperatures were measured in a sleeping posture at air temperatures of 21℃, 24℃, 26℃ and 29℃. Mean skin temperatures were calculated using a formula with 10 measuring locations on the skin. The thermal comfort levels and thermal sensation of the subjects were also investigated by questionnaire. Based on the experimental data, an evaluation model of an individual’s thermal comfort using mean skin temperature was developed using the Mahalanobis distance discrimination method. Seventy two per cent of the total subjects’ thermal comfort levels was correctly evaluated using this evaluation model. The evaluation models were further improved by a consideration of the gender difference in mean skin temperature. The study revealed that the human mean skin temperature could be used as an effective physiological indicator to reflect an individual’s thermal comfort under steady thermal environment. The proposed evaluation model based on mean skin temperature provides an effective and simple method to evaluate an individual’s thermal comfort in a sleeping posture under steady thermal environment.