In this study, the two flat plate collectors, which have aluminum and copper absorber surface type, and other features of which are identical, were tested in the experimental setup having the sun seeker system and conforming to TS EN 12975-2. Energy efficiencies of solar collectors were calculated and compared as specified in TS EN 12975-2 by using solar radiation and water inlet-outlet temperatures. As a result of the comparison, it was determined that the efficiency of the collector having aluminum absorber surface is higher up to 40 degrees C, while the efficiency of the collector having copper absorber surface was found to be higher at temperatures higher than 40 degrees C. Exergy efficiency of collectors were also calculated and compared. It was observed that the exergy efficiencies of collectors are the 0,037 up to about 55 degrees C, while the exergy efficiency of the collector with the copper surface absorbent area was 0.064 while the exergy efficiency of the aluminum absorbent surface collector was 0.059 when the temperature was increased to about 70 degrees C. When the temperature was increased to about 80 degrees C, the efficiency of exergy was observed to decrease in both collectors. The exergy efficiency of the copper surface collector decreased to 0.056, while the exergy efficiency of the aluminum surface collector decreased to 0.051.