Abstract: A clip fastening system for securing a window in a window opening without the use of penetrating fasteners is disclosed. The clip fastening system includes a flange that extends in an inward direction from and around the window opening, a groove that is formed through a facing of a window frame of the window and that extends around the perimeter of the window frame, and a clip mutually engaged with the flange and the groove, thereby securing the window frame within the window opening.

Abstract: A screwless window fastening system has a frame having an exterior surface, an interior surface, and a peripheral wall extending between the exterior and interior surfaces. The peripheral wall has an inward facing surface forming a window opening for receiving a window assembly through the exterior surface. At least one window clip has a window frame receiving channel and is attachable to a window frame of a window with the window frame disposed in the window channel to form an assembly that is insertable into the window opening. And when the assembly is inserted into the window opening, the at least one window clip engages with the frame to prevent withdrawal of the assembly from the window opening.