The effects of external baffles on heat and mass transfer to an air-to-water copper finned-tube cross-flow heat exchanger are considered. The four-tube, two-pass coil was operated over a Reynolds number (based on hydraulic diameter and maximum core velocity) range from 400 to 1500. A method of correlating condensation mass transfer data, based on the saturation enthalpy at the water temperature, is reviewed. Convective heat and mass transfer coefficients are presented as plots of Co/burn j-factor vs. Reynolds number. The presence of baffles is found to augment the transfer coefficients over the range of Reynolds numbers, the effects becoming greater at higher flow rates. Only one type of heat exchanger is considered.