The built environment is among the highest energy consuming sectors worldwide. However, buildings have large surface areas that can be used to improve the building energy performance. One example is by integration of photovoltaic systems in roofs and facades, which can reduce the carbon footprint of the built environment. An emerging field that could lead to energy savings involves the glazing. Switchable or smart windows allow for a variable transparency which affects the amount of incoming daylight and solar heat. Manually controlled smart windows however, require electricity to function and could thus be powered by solar energy to function autonomously. Smart windows have been shown to improve the building energy performance by reducing heating, cooling and lighting loads and can also be used to optimize the visual and thermal comfort conditions of occupants. In this thesis project the energy performance of three types of switchable glazing has been compared to different window technologies including electricity generating photovoltaic windows. Additionally, the hourly and yearly electricity requirements of each smart window and the corresponding minimal photovoltaic system requirements have been determined.