Windows are one of the main components in homes and buildings. They have the purpose of providing light and ventilation, allowing through it the communication from the interior to the exterior. The two functions are allowed thanks to mechanisms of opening and closing and glazed materials. In terms of energy, they represent an unwanted source of heat gain in summer and heat losses in winter affecting our climate comfort, which is reflected in the energy consumption for the conditioning of the rooms. This is because the thermal performance of a window depends on the environmental climatic conditions in which it is located. To contribute to saving energy in buildings, the main objective of windows is to prevent the passage of heat inside in warm weathers and to keep the heat inside the building in cold ones. Nowadays, buildings are responsible for consuming between 30 % and 40 % of the energy used in most countries. This is the reason why it is necessary to build up efficient buildings. An efficient home is one that takes full advantage of the climate and energy resources of the place to achieve comfort in a natural way. Efficient homes are cooler in summer and warm in winter. They achieve this by consuming less energy than conventional homes and reduce the dependence on artificial means of cooling and heating. All efficient housing must have the following characteristics: design, materials, completions and construction techniques appropriate to the climate of the place. In the thesis, in addition to presenting the theoretical framework, a practical case related to solar control films will be counted. The case what studied in 3 different Climates and in the 4 orientations for its conclusion. TFGM