Controlling light and heat radiation through windows and glass facades at the push of a button, saving energy and still maintaining a clear view? Switchable electrochromic films that turn dark but remain transparent are expected to make this possible in the future. The fact that this can also be retrofitted in existing buildings is to be demonstrated by the joint project “EnOB: FLEX-G 4.0 – Technologies for innovative switchable films as a retrofit solution for energy-saving windo...