AbstractIn order to reduce the building's energy demand, different glass innovative technologies are currently under intensive research and development. However, applicability of a particular technology requires its extensive environmental and energy characterization in building integration. In this work, overall performance (thermal, optical, and electrical) of semitransparent PV windows from different technologies has been assessed and compared with conventional windows. Characterization studies include both field measurements and numerical simulations and reveal the energy saving potential of PV windows on the overall energy demand of an office room and Mediterranean climate conditions. Finally, building integration is optimized by maximizing energy efficiency while keeping acceptable indoor visual comfort for different PV technology, ratio of the glazing surface replaced by PV windows (cover ratio), and orientation.