For the past 50 years, much effort has been expended on the study of thermal comfort. Two basic approaches have been used. One is direct experimental evaluation of the subjective response of human subjects exposed to various thermal environments (10,11, 12, 14, 19,22,29). The other is correlation of observed physiological data with expressions of thermal comfort (5, 6, 28, 29).

Complete definition of the relationships between thermal comfort and the various environmental thermal factors can be accomplished through exhaustive experimental testing. However, for the range and number of thermal variables influencing comfort, a direct experimental approach is relatively expensive and time-consuming. Recent developments in modeling the thermoregulatory system of man suggest an alternative and an aid to experimental work through the development of a physiological model for thermal comfort. Such a model would be of great utility in planning future experimental work, in correlating existing data, and in predicting response in areas not yet investigated.