The manufacturing, installing and fixing the windows have very important roles in the quality of windows. The events that the windows lose great amount of heating by the parts that meet the building walls and the side walls become chilled, frosted and condensated or sweated are related to the window fixing. Therefore, we have introduced the plastic interior fixing with the windows’ thermal insulations of the WIN PLAST Company of Russian Federation into our production activity. The advantages of this interior fixing are that the installation period of the windows fixture is short, clean and good appearance, sound proof, easy to clean and surrounding areas of windows have good appearance. The window production, installation, and fixing have very important roles in the windows’ quality.