A solar air heater is a simple, low-cost, sustainable heat exchanger that may be used for industrial, household, and agricultural drying processes. It can also be used to heat homes and other buildings. In comparison to smooth absorbers, artificially roughened absorbers can greatly increase the thermal performance of solar air heaters. In this study, the thermohydraulic performance of a solar air heater with rough C-shaped ribs was analytically investigated. The findings of the examination of the thermal efficiency, exergy, and entropy were compared to the results of a smooth duct. The thermal-performance of the C-ribs absorber is significantly greater than that of the smooth duct. The Nu is 4 times the smooth duct, and the mean thermal efficiency percentage growth is around 40%. This study presents a novel approach to SAH sustainability. The optimum values for maximum thermal performance are (e/D) = 0.0422, (α/90) = 0.33, and P/e = 10. The several thermal energy losses that cause the SAH's thermal performance to deteriorate have been identified. According to the current study, the typical thermohydraulic performance parameter is 3, which is greater than the typical roughness.