A serious difficulty in the heating or cooling of buildings lies in reconciling conflicting comfort requirements of men and women. A temperature that is comfortable to men is as a rule too cool for women, and one that is acceptable to women is too warm for men. As a result buildings are usually overheated in winter for the sake of women and overcooled in summer to suit the men. Constitutional differences between men and women as well as differences in kind and amount of clothing worn are believed to be responsible for the double comfort standard, but according to the present study clothing differences appear to play a major role. The experiments were carried out in an air conditioned room by exposing healthy men and women subjects, mostly employes of the school, to ordinary air conditions that prevailed in the laboratories and offices of the school on the day of