Installations integrated in buildings are among the most promising applications of photovoltaic systems. The power generated by photovoltaic modules is supplied to the internal network of the user building and, at the same time, to the public distribution network. In this way, according to the needs, it can be used by local users or supplied to the network. Photovoltaic modules can be used to cover buildings as a replacement of traditional components. With this objective, the photovoltaic and the building industry have created some architectonic modules that can be integrated with the building structure. They are more and more used on building fronts and to cover buildings. The possibility to integrate photovoltaic modules into architectures and transform them into building components has widened the range of application of the photovoltaic and architectural sector, that exploit this type of energy. A particularly interesting use consists of “photovoltaic facades”.