An experimental study of a fin-and-tube heat exchanger was performed in two different configurations (single and three-screen mode). To this end, a test rig was constructed to evaluate the heat transfer capacity on the air side and water side. A wide range of Reynolds numbers on the air side was investigated. A series of measurements was performed with uniform inlet flow conditions. These served to determine the heat transfer correlation for the fin type using the Wilson plot method. No correlation was available, as the fin is an adapted inclined louvered type. To validate these results, a thorough uncertainty analysis was performed. Parallel to the experiments, a simulation program was written, designed to take non-uniform flow into account. The program is based on a local (section by section) analysis scheme. To validate the program, a series of non-uniform measurements was performed. Results showed that the program is able to predict the impact of non-uniform inlet flow conditions. The numerical code can be used as a design tool to develop more efficient heat exchangers.