A personal environment module (PEM) task air conditioning system as an alternate air conditioning system for improving thermal comfort in workspaces is studied. Air temperature and velocity distribution characteristics of the PEM built and installed in an environmental chamber (EC) were evaluated. Comparisons were made with a typical under floor air conditioning (UFAC) system. The EC enabled creating appropriate weather conditions and performing tests simultaneously under similar load conditions. Results show that in general, the PEM maintained higher air flow rates and good temperature in the room compared to the UFAC system. Being flexible and easy to control, PEMs offer significant potential to improve thermal comfort in workspaces. (C) 2001 Elsevier Science Ltd. All rights reserved.