This study presents the results of a numerical and experimental study of the position of the baffles in a solar air heater in order to improve its thermal and hydraulic performance. The numerical study was performed on four cases corresponding to different placements of baffles with Reynolds numbers ranging from 2370 to 8340. The experimental model of the solar air heater was designed, manufactured and used for the validation of the numerical model. The new baffle placements show that effective thermo-hydraulic performance is not just a function of the shape or changes in the geometric parameters of the baffles. The correct placement of baffles dramatically improves the thermo-hydraulic performance of solar air heaters. The effect of baffle positions on local convective heat transfer coefficients has been discussed. The optimum thermo-hydraulic performance factor is achieved in the case where the baffles are located in the first part of air channel which occupies 50% of the solar air heater. (C) 2020 Elsevier Ltd. All rights reserved.