Abstract This study investigates the performance of two solar air heater designs, S1-SAH and S2-SAH, through experimental analysis of temperature, energy gain and loss, efficiency, and Thermal-Hydraulic Performance Parameter (THPP) across mass flow rates ranging from 0.013 to 0.061 kg/s in hot climatic conditions of R.E.C Banda. The S2-SAH consistently outperformed the conventional S1-SAH, achieving a maximum energy efficiency of 79.3% at 0.051 kg/s and a peak exergy efficiency of 4.5% at 0.013 kg/s. Additionally, the highest THPP of 2.0 was recorded at 0.051 kg/s. The results highlight the superior performance and enhanced efficiency of the S2-SAH, showcasing the effectiveness of its design for improved heat transfer.