The performance of crystalline silicon photovoltaic module is mainly determined by the efficiency of silicon cells, but the performances of other components, such as the encapsulant, the front glass and the backsheet, also have an impact. Among these, the optical properties of the backsheet are critical in determining the performance of the photovoltaic module as higher reflectance of the inner side of the backsheet helps redirect more reflected light back to the photovoltaic cell. In addition to the optical properties of the backsheet, the durability of the backsheet should be taken into account due to its role in ensuring a module lifetime of 20-25 years. The backsheet protects the module and its components from external stresses and also acts as an electric insulator. In this study, we focused on the performance and degradation of different types of backsheets and how these impact the performance of the module. We investigate how the initial optical performance of the backsheet impacts the performance of the module. After degradation at 85 degrees C and 85% relative humidity over 4000 h, reflectance and module performance were correlated and compared with its initial performance. (C) 2015 Elsevier B.V. All rights reserved.