In the present paper, an experimental analysis of the PV modules efficiency of different photovoltaic comprising monocrystalline silicon, polycrystal-line silicon and thin-film silicon technologies has been made. The PV modules were first subjected to thorough indoor evaluation (Sun simulator, Electroluminescence) to check the real characteristics and internal defects that make the effectiveness of these modules lower compared to characteristics declared by the manufacturer under the terms of DIN EN ISO/IEC 17025:2005. Results of the first analysis have been taken as a reference for the second part, which consist of ex-posing the PV modules to various natural factors in outdoor environment (solar radiation, temperature, wind, humidity…) versus time. Then, using the peak power measuring device PVPM, different electrical characteristics of the photovoltaic module during the exposure in operating site were determined. Significant differences in the energy efficiency of PV modules have been presented. The analysis of the photovoltaic efficiency has allowed a better comparison between PV technologies better for a specific environment (semi-humid region).