This article presents the study and application of techniques for evaluating photovoltaic modules, in relation to dirt, temperature along with the main forms of visual degradation to which the materials constituting the photovoltaic modules of multicrystalline technology may be subject and their respective impacts on the performance of the generation of electric energy. To this end, 48 photovoltaic modules were analyzed from 5 different models, which totaled a power peak of 10.16 kWp derived from the photovoltaic system installed at the Research laboratory of Power Electronics at the Federal University of Uberlandia-Brazil (NUPEP-FEELT-UFU). Initially, all the modules were appropriately cleaned. With the purpose of evaluating any endured degradation, a visual inspection was performed, and for the analysis of heat distribution across the surface of the modules, thermographic images were obtained and evaluated with the aim of identifying hots-pots, then these signs were related to the degradation identified during the inspection. In addition, with the objective to quantify the impact of failures in electrical performance, the curves I-V and P-V were measured in loco in 2017 and 2018, both individually and as a string, in order to obtain the main electric parameters. (C) 2019 Published by Elsevier Ltd.