Building retrofit offers the opportunity to reduce energy consumption, improve energy efficiency and increase the use of renewable energy sources. The photovoltaic (PV) technology can be integrated into the building envelope, where conventional construction materials can be easily substituted by PV modules. Prices are competitive with some other solutions and good architectural building integrated photovoltaics (BIPV) solutions enhance the appearance of the buildings. All this makes BIPV an attractive solution for effectively and sustainably retrofitting building envelopes, providing savings in materials and in conventional electricity consumption and, at the same time, improving the energy efficiency of the buildings. This paper shows a building retrofit case study in which standard PV modules are integrated into a new ventilated façade, aiming at serving as an easy-to-implement example for large-scale actions.