In this study, a set of experiments were conducted in a hot and humid climate to evaluate subjects behavior in operating an individually controlled personalized ventilation system. The system was equipped with individual control of airflow rate. The effect of the control system on thermal comfort and the responses of subjects were studied. Forty-six tropically acclimatized subjects participated in the experiments that were conducted in a field environment chamber served by a desk-mounted personalized ventilation system integrated with an ambient mixing ventilation system. Ambient temperatures of 23° C and 26° C (73.4F and 78.8F) and personalized ventilation air temperatures of 20° C, 23° C, and 26° C (68F, 73.4F, and 78.8F) were employed. The results showed that more than 90% of subjects felt the thermal environment was acceptable, irrespective of the ambient temperature and personalized ventilation air temperature. Subjects preferred airflow rates showed a large variation from 0 to 16 L/s/person (33.9 cfm/person), which supports the case for individual control. When the ambient temperature was 26° C (78.8F), subjects whole body and body parts thermal sensations were closer to neutral, which indicates that whole body thermal sensation was largely improved. © 2012 Taylor and Francis Group, LLC.