In this paper, we present a method of calculation by partial or total condensation of the water vapor contained in the humid air, over the smooth or finned tubes-heat recupurators. This study presents an implantation of the film method in a computer code developed here. The mathematical model used is validated by our experimental approach, using tubes bundles in staggered and aligned arrangements. The heat transfer coefficient by convection around the fin is supposed too be constant. The computer code predicts the heat flux exchanged in a range of 20% and 5%, in wet and dry regime, respectively. The apparent heat transfer coefficient by condensation can exceed 10 times the value of the heat transfer coefficient. The mathematical model used is validated with the experimental data obtained in this study.