The aim of this experiment is to investigate the differences of the generated powers for the roof azimuth on the a-Si PV module developed for direct installation to the roof of wooden houses. The automated measuring system has been constructed to measure the generated powers, the module temperature,and the irradiation for each module from 6 AM to 6 PM with the time interval of 10 min. The system has started from May 1999, and in this paper, the automated measuring system and the analyzed results for eight months are presented, (C) 2001 Published by Elsevier Science B.V. All rights reserved.