This study investigates the influence of fins and baffles attached over the absorber plate on the performance of the upward type single pass solar air heater. A steady-state mathematical model is presented and solved theoretically. The performance evaluation is studied in terms of different performance indicators, such as outlet air temperature, efficiency and effective efficiency. It is found that attaching fins and baffles effectively increases the outlet air temperature and efficiency in comparison to a simple conventional device. However, it is observed that increasing the number of fins and baffles parameters can reduce effective efficiency even less than a simple conventional device in some cases due to the high required pump work. It is found that there is no chance of introducing unique optimum number of fins and baffle parameters in all mass flow rates to achieve the highest performance in terms of effective efficiency, but it can be obtained in constant mass flow rate. The results reveal that the baffle width is a crucial parameter when the Reynolds number increases and the flow regime is turbulent. Increasing the solar intensity leads to achieve higher outlet air temperature and efficiency as well as lower difference between efficiency and effective efficiency. (c) 2013 Elsevier Ltd. All rights reserved.