Windows coated with all-season climate films for flat glasses in windows and doors contribute quickly and significantly to the increase in energy efficiency of buildings. The steady indoor temperature enhances the sense of well-being, protects against unnecessary solar irradiation and prevents high heat loss, and simultaneously reduces energy costs for space heating and cooling. The radiation energy is reduced and the thermal insulation value gets sustainably improved. There is a sustained reduction in costs of space cooling, wear and tear of heating, ventilation and air-conditioning systems, as well as CO2 emission of buildings.