Performance of building integrated energy systems is highly sensitive to a precise combination of parameters that was chosen on the design stage. Most of the time, these parameters are interdependent and difficult to balance. Application of modern technologies together with newly developed optimization methodologies made it possible for architects and engineers to generate high-quality configurations of such energy systems. However, how reliable and robust the end results are, is often an open question. Apart from efficiency of optimization algorithm that can influence the results, operating conditions might be unstable and differ from the ones considered in the design stage. This master study presents a simulation-based investigation of how changes in weather conditions might affect the performance of once optimized photovoltaic integrated shading device (PVSD). The goal is to explore whether an optimized PVSD design solution will remain robust as the best performing solution. Methodology of the research consists of full factorial parametric analysis of homogeneous photovoltaic louvre-blade system with four variables. Three of these variables define geometrical characteristics of the system, i.e., number of evenly spaced louvres, their size and tilt angle. The fourth variable is a meteorological data. The study covers 3 different climate types and 24 variations of weather data with an individual degree of difference. The results indicate that evaluation of robustness for design and optimization of PVSD is an important part of the process. It helps to increase the quality of the design solutions for integrated shading solar facades. In this study, best performing PVSD configurations turned out to be robust under fluctuations of weather boundary conditions. In addition, these configurations remained to be the optimal design solutions even when the type of climate was changed.