In recent years, offices have tended to emphasize the comfort of individual office workers. Equivalent temperatures using thermal manikins have been used to assess the performance of PCS. However, the equivalent temperatures do not consider latent heat losses such as respiration, dead heat excretion and perspiration. The performance evaluation of PCS needs to take latent heat loss into account. Therefore, the amount of sensible and latent heat loss during PCS use was analyzed. In addition, a new thermal environment evaluation index called site-specific ET*, which takes latent heat loss into account, was proposed and the cooling effects of each site were verified and analyzed under sitting rest. The results showed that under condition, the site-specific ET*, which considers latent heat losses, showed a greater temperature decrease due to airflow exposure than the equivalent temperature used to assess the performance of conventional PCS, indicating that latent heat losses influence the temperature experienced when using PCS.