The concept of an architectural switching film based on solid-state electrochromism is introduced. Electrochromic films have the ability to dynamically control solar transmission through a glazing and to alter the energy conduction properties of the window. Switching properties of transition metal oxides based on tungsten and iridium are detailed. The properties of WO3-based films, which can modify both the visible and near-infrared portions of the solar spectrum, are given.