A four-pass cross-flow heat exchanger was developed and manufactured in this practical study for two types of tubes: smooth and triangular finned tubes. The length of the tube is 250 mm, for a smooth tube the inner and outer diameter (19, 21 mm), and (19, 21 and 24 mm) the inner, outer diameter and the fin root for the finned tube respectively. Water is used as a hot fluid inside the tubes and air is used as a cold fluid outside the tubes. Inlet hot fluid temperatures were 50, 60, 70, and 80 °C, with three air speeds (1, 2, and 3 m/s), and volumetric flow rate (2, 3, 4, and 5 l / min) held steady at 25 ° C. The finned tube outperformed the smooth tube in terms of heat transfer rate, heat transfer coefficient, total heat transfer coefficient, and effectiveness, according to the findings.