The 13 integrated photovoltaic modules Solarwatt (M234-108 GEG LK) are standard black glass–glass panels made of 108 monocrystalline cells. The ‘glass-glass’ technology, where solar cells are between two glass panes rather than of standard glass and plastic back-sheet setup, is considered as an extremely durable and resistant solution, with an optimal cells protection. The PV plant is the top layer of an insulation element consisting of a metal sheet, an insulating layer and a concrete structure. An air gap (8 cm) is left between the panels and the metal sheet in order to allow natural ventilation. The modules are mounted as common curtain wall component. They are fixed to an aluminium frame made of cross and vertical beams, hiding the wiring system.