The solar air heater is one of the solar energy applications used to heat the atmospheric air for space heating and drying applications. Due to the formation of the laminar viscous sublayer convective heat transfer coefficient of the absorber plate is low. An attempt is made to improve the efficiency by creating perforation holes of different shapes (circular, triangular and rectangular) on the top surface of the absorber duct insert placed inside the test section of the Solar Air Heater (SAH). The absorber duct insert enhances the heat transfer rate, and perforation causes the cross flow and the flow disturbance in the flow stream. A rectangular-shaped hole configuration shows the highest thermal efficiency of 87.01 %, followed by the circular and triangular hole configurations. Circular hole configuration shows the highest thermo-hydraulic efficiency of 83.01 % at the Reynolds number of 15000.