An experimental study has been carried out to investigate the heat transfer and pressure drop characteristics of fin-and-tube exchangers with plate, wavy and louvered fin surfaces. In all, 36 samples of heat exchangers, including 12 plate-fin, 12 wavy-fin and 12 louvered-fin geometries, were tested. Results are presented as plots of friction factor f and Colburn j factor against Reynolds number in the range 300-2000. Additionally, the dimensional heat transfer coefficient and pressure drop are also presented against frontal air velocity. Finally, various comparison methods were adopted to evaluate the air side performance of the plate, wavy and louver fin heat exchangers. (C) 2000 Elsevier Science Ltd. All rights reserved.