The finite difference method in conjunction with the least-squares scheme and the experimental temperature data is proposed to predict the average heat transfer coefficient and the fin efficiency oil the fill inside one-tube plate finned-tube heat exchangers for various air speeds and the temperature difference between the ambient temperature and the tube temperature. Previous works showed that the heat transfer coefficient oil this rectangular fin is very non-uniform. Thus the whole plate fill is divided into several sub-fin regions in order to predict the average heat transfer coefficient and the fill efficiency oil the fin from the knowledge of the fin temperature recordings at several selected measurement locations. The results show that the surface heat flux and the heat transfer coefficient on the upstream region of the fin call be markedly higher than those on the downstream region. The fill temperature distributions depart from the ideal isothermal situation and the fin temperature decreases more rapidly away from the circular center, when the frontal air speed increases. The average heat transfer coefficient on the fin increases with the air speed and the temperature difference between the ambient temperature and the tube temperature. This implies that the effect of the temperature difference between the tube temperature and the ambient temperature is not negligent. (c) 2005 Elsevier Ltd. All rights reserved.