Abstract: Three sides 60° wire roughened solar air heater together with on side 60° wire roughened solar air heater has been investigated. Effect of roughness and flow parameter, p/e, e/D and Re on thermal performance of the collectors has been represented. Three sides 60° wire roughened solar air heater has been found to be thermally more efficient by an amount of about 14-46% than that of one side roughened one in the range of parameters investigated.