Installation systems and methods for fenestration units configured to be set into a rough opening (RO) from interior side of a building structure or wall. The fenestration units may include a retention system coupled to the frame and operable to exert a retention force on the fenestration unit to maintain positive engagement of the fenestration unit with the rough opening framing and resist extraction of the fenestration unit from the rough opening upon insertion of the fenestration unit in the rough opening from the interior side of the rough opening.

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.

The present disclosure concerns a foundation window assembly comprising a window frame comprising a plurality of frame members, and at least one casing connector arranged on at least one of said plurality of frame members; and a window casing comprising a plurality of casing members defining together a frame-receiving opening, wherein at least one of said plurality of casing members defines a frame-abutting shoulder at least partially delimited by a casing flange portion and a frame-engaging portion. A frame-engaging recess is formed in the frame-engaging portion, the frame-engaging recess at least partially circumscribing the frame-receiving opening, the casing connector being removably engageable into the frame-engaging recess when the window frame is inserted into the frame-receiving opening. The present disclosure also concerns a method for installing a foundation window frame into a foundation wall.

Installation systems and methods for fenestration units configured to be set into a rough opening (RO) from interior side of a building structure or wall. The fenestration units may include a retention system coupled to the frame and operable to exert a retention force on the fenestration unit to maintain positive engagement of the fenestration unit with the rough opening framing and resist extraction of the fenestration unit from the rough opening upon insertion of the fenestration unit in the rough opening from the interior side of the rough opening.

Installation systems and methods for fenestration units configured to be set into a rough opening (RO) from interior side of a building structure or wall. The fenestration units may include a retention system coupled to the frame and operable to exert a retention force on the fenestration unit to maintain positive engagement of the fenestration unit with the rough opening framing and resist extraction of the fenestration unit from the rough opening upon insertion of the fenestration unit in the rough opening from the interior side of the rough opening.

A window assembly includes an inside frame, and outside frame, a glazing panel and a set of connectors that serve to seat, or positively locate, the glazing panel relative to one of the frames, and also positively to locate the inside and outside frames relative to each other. The members of the frames and the connectors may all be extrusions. The connector may have non-releasing, one-way engagement fittings that snap fit together with mating fittings on the frames. The frames may be made of a metal such as aluminum. The connectors may be made of a thermal insulator, such as a plastic of other composite material, that may tend not to form a thermal bridge between the inner and outer frames.

Installation systems and methods for fenestration units configured to be set into a rough opening (RO) from interior side of a building structure or wall. The fenestration units may include a retention system coupled to the frame and operable to exert a retention force on the fenestration unit to maintain positive engagement of the fenestration unit with the rough opening framing and resist extraction of the fenestration unit from the rough opening upon insertion of the fenestration unit in the rough opening from the interior side of the rough opening.

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.

Installation systems and methods for fenestration units configured to be set into a rough opening (RO) from interior side of a building structure or wall. The fenestration units may include a retention system coupled to the frame and operable to exert a retention force on the fenestration unit to maintain positive engagement of the fenestration unit with the rough opening framing and resist extraction of the fenestration unit from the rough opening upon insertion of the fenestration unit in the rough opening from the interior side of the rough opening.