The air side performances of two louvered fin surfaces under dehumidifying conditions were examined in this study. The test results indicated that the effect of fin pitch on the heat transfer performance is comparatively small, and the friction factors increase significantly with fin pitch for fully wet conditions. The effect of inlet relative humidity on the sensible heat transfer performance is negligible. However, there is a detectable effect of inlet condition on the friction factors for type (I) louver due to condensate retention. A correlation of heat, momentum, and mass transfer was proposed to correlate the present database with a mean deviation of 5.94%, 6.1%, and 7.89%, respectively.