Considerable improvement in the collector efficiency of solar air heaters is obtained if the fins in the collector have attached baffles to create air turbulence and an extended heat-transfer area. Further improvement in performance can be achieved if the fins with baffles are attached over the absorbing plate in such a manner that air flows over, instead of under, the absorbing plate and creates free convection. In this paper, energy balances for upward-type baffled solar air heaters have been developed and a theoretical equation for estimating the collector efficiency has been derived.