ABSTRACT Development in solar air collectors have increased because of the renewable and non-polluting sources of energy. The present study focused on artificial roughness, vortex generators, thermal storage units, etc., which are employed to improve the performance of Solar Air Heaters (SAHs). Thermal efficiency of Double Pass Solar Air Heater (DPSAH) improved from 10% to 15% as compared to the Single Pass Solar Air Heater (SPSAH) and improves further using an integrated absorber with a heat storage unit. About 12% and 15% improvement in thermal and thermo-hydraulic efficiency was achieved using a rough absorber. Integrated absorbers with Composite Phase Change Materials (CPCMs) based heat storage is one of the new signs of progress to optimize the thermal efficiency of SAHs.