Wind energy applications have rapidly increased in the world, so the efficiency of wind energy constructions is gaining importance. Using small wind turbines, farmers, ranchers, and homeowners can reduce their utility bills, stabilize their electricity supplies, and contribute to the nation's energy supply, and thus play an important role in securing our energy future. Distributed wind electric systems represent an opportunity for some nations in particular. This study aims (i) to investigate the efficiency differences between three bladed glass reinforced plastics (GRP) rigid hubs, three bladed steel rigid hubs and twelve bladed steel rigid hubs experimentally, and (ii) to improve the performance of the small wind turbine system (SWTSs) installed at the Solar Energy Institute of Ege University (latitude 38.24degrees N, longitude 27.50degrees E), Izmir, Turkey. NACA 4415 (National Advisory Committee for Aeronautics) series blades are preferred to others in this experiment, because of the fact that this profile has shown excellent properties for small wind turbine blades and their average power coefficients are higher than those of other blades. In this study, the performance parameters of the SWTSs are given first. An experimental study is then presented. Finally, the results obtained from the present study are discussed. (C) 2003 Elsevier Ltd. All rights reserved.