The solar air heater with a hemispherical shape obstacle has been introduced, and an experimental study has been conducted to explore their performance over an extensive scope of running environments. The collector efficiency can be enhanced by increasing the heat transfer surface area by incorporating fins or obstacles to either over or under the absorbing surfaces. Different operating conditions have been chosen to run the experimental setup. Various measurable parameters like temperature of absorbing plate, temperature of inlet and outlet air, temperature of ambient air and solar radiation have been measured. The mass flow rates in the flow channel duct have been changed and measured to conduct the experiments for study the variation in performance for both finned and smooth absorbing plates. The study was concluded with calculation of the collector efficiency and reported a significant improvement in efficiency with hemispherical fins on absorber plates. © Springer Nature Singapore Pte Ltd 2021.