This paper shows the comparison of two grid connected photovoltaic systems GCPVS that are operating in the city of Bogotá - Colombia for more than three years. The systems are constituted by one of 0.8 kWp and the other of 3.6 kWp, they were designed with different dimensioning factor FD. The results revealed that the systems has different performance ratio PR, one of 0,78 for the one of 3,6 kW and 0,5 for the other of 0,8 kW.