glassAdvisor is a commercial web-App that supports professionals in the design of glazing systems. Among the different calculation modules, i.e. acoustics, statics, and energy transfer, a new thermal module has been developed for the detailed calculation of glazing systems including shading devices. This last feature increased the tool’s potentiality in calculating complex transparent façade elements, which today is of major importance for the correct design of the new façade technologies available in the market. Additionally, static calculations with fixed winter/summer boundary conditions are not sufficient for understanding the real behavior of the façade. In this context, the opportunity offered by Open Data in retrieving reliable climatic data, such as air temperature and irradiance, is of great importance. The use of the Open Data combined with the detailed calculation for the façade design in the tool glassAdvisor will be presented.