The present work predicts the thermal and thermohydraulic performance of the extended surface absorber solar air heating collector equipped with twisted tape inserts of twist ratio Y = 2, 4, 6 and 8. A mathematical model has been formulated based on energy conservation equations of the various elements of the collector under consideration. The model is numerically solved using the MATLAB codes. Effects of mass flow rate, twist ratios and the solar intensity of the performance of the heater have been investigated. The results obtained are compared with the results of conventional and finned absorber solar air collector. Results conveyed that at mass flow rate of 0.025 kg/s, with increase in solar intensity from 500 W/m(2) to 1000 W/m(2), the thermal efficiency of the collector with twist ratio Y = 2 increases by 8.3%. Furthermore, integrating fins and twisted tape (FTTs) with the absorber plate, a maximum enhancement of 22.56% in the thermal efficiency has been achieved as compared to 11.49%, when only fins are attached. This maximum enhancement is observed with the tape with minimum twist ratio. Hence, the collector having absorber plate attached with fins and twisted tapes of twist ratio Y = 2 is the most efficient.