The present study deals with solar collectors on the basis of exergy analysis. A criterion is proposed to rank the performance of different solar collectors. There are two considerations involved, namely, the quantity and the quality of the annually collected energy. Rabl's method was used to predict this quantity. The average temperature of the delivered energy must be determined in order to evaluate its quality. The HWB performance equation is employed to predict the average delivery temperature of hot water, assuming a reference insolation of 550 W/m2. The exergy content of the delivered energy is then evaluated by multiplying the delivered energy by the Carnot efficiency. The annual collectible exergy is used to rank the performance of a collector. According to the concept developed in this study, this criterion can be used for any type of collector, e.g., flat-plate, evacuated tube, CPC, tracking concentrators, or central receivers.