Due to the current climate shift and increased energy consumption, alternative energy sources are being sought for building heating, industrial heating, and agricultural drying which are some of the uses for the versatile, affordable, and ecological solar air heater heat exchanger. Solar air heaters can obtain much higher thermal efficiency by utilizing specifically roughened absorbers rather than smooth ones. The present study presented the analytical and computational fluid dynamics (CFD) approaches for solar air heater to identify the thermal performance. An absorber plate made from aluminum is considered for the investigation with a V-shaped roughness. A smooth absorber plate’s finding and the analyses were contrasted, with special emphasis on the SAH's thermal performance. The V-ribbed absorber exhibited a remarkably 40% greater thermal efficiency and five times higher Nusselt number compared to the smooth absorber duct. However, it has been observed that the optimum parameters to attain the best thermal performance, such as relative roughness height = 0.043 and angle of attack = 0.66. Furthermore, the thermal hydraulic performance is found to be maximum at Re = 12,000.