Solar air heaters are used for applications at low and moderate temperatures such as; crop drying, timber seasoning, and space heating. In the present work efforts are made to enhance the heat transfer rate and to improve the efficiency of simple fabricated solar air heater. "Granular carbon", has introduced as a long term heat absorbing media inside solar heater. The thermal performance evaluation of solar heater has been carried out on four different configurations by operating it on natural and forced convection. The thermal behaviour of the system has also been evaluated by operating it on auxiliary power by placing a halogen tube (300 W) inside the inlet and outlet ducts. Because of using halogen lights the system is feasible to perform in night or bad climatic conditions. The thermal performance of all new configurations was found better in comparison of conventional solar air heater on both natural and forced convection. (C) 2012 Elsevier Ltd. All rights reserved.