To be expressed in a professional language, then the windows made of plastic with two glasses are called single -chamber, of three glasses is a two -chamber double -glazed window, because the number of cameras is much more important than the number of glasses. Two -chamber double -glazed windows that have three glasses are called double. It is thanks to the layers of inert gas or air in the windows of plastic and the sound and thermal insulation of the room from the environment is provided.