A fenestration assembly includes a glazing unit includes a pane spacer between exterior and interior panes proximate glazing unit edges. A fenestration frame is coupled around the glazing unit and includes a frame core extending around the glazing unit. The frame core includes a unitary core wall including a composite material that is hollow and extends continuously from a core interior face to a core exterior face. A metal glazing cap is coupled with the frame core. The metal glazing cap having a cap end indirectly engaged with the glazing unit along the interior pane, and the cap end is remote from the pane spacer. Each of the core exterior face, the pane spacer and the metal glazing cap are thermally isolated from each other with the frame core including the unitary core wall.

There is included an intermediate element including one or more, but not necessarily limited to, an L-shaped profiled portion configured to receive a part of a panel of a door or window, a pad configured to be fit into at least one frame part and comprising a support strip groove, and an intermediate element extended from the L-shaped portion to the pad.

There is included an intermediate element including one or more, but not necessarily limited to, an L-shaped profiled portion configured to receive a part of a panel of a door or window, a pad configured to be fit into at least one frame part and comprising a support strip groove, and an intermediate element extended from the L-shaped portion to the pad.

A window attachment system for attaching a window to an opening in a building includes a male portion and a female portion. One of the male portion and the female portion is attached to one of the outer perimeter of the window frame or the inner perimeter of the opening in the building. The other of the male portion and the female portion is attached to the outer perimeter of the window frame or the inner perimeter of the opening in the building. The male portion is engaged with the female portion when the window is placed into the opening.

A window attachment system for attaching a window to an opening in a building includes a male portion and a female portion. One of the male portion and the female portion is attached to one of the outer perimeter of the window frame or the inner perimeter of the opening in the building. The other of the male portion and the female portion is attached to the outer perimeter of the window frame or the inner perimeter of the opening in the building. The male portion is engaged with the female portion when the window is placed into the opening.

An integrated sash unit including a first sash portion. The first sash portion a first body portion and a first receiving wall extending inwardly from the first body portion. The first receiving wall has a first inner wall surface and a first peripheral wall surface opposing the first inner wall surface. The first body portion defines a first receiving surface and a first coupling surface and a first body peripheral surface opposite the first receiving surface and the first coupling surface. The integrated sash unit also includes a second sash portion forming a second body portion and a second receiving wall extending inwardly from the second body portion. The second receiving wall has a second inner wall surface and a second peripheral wall surface opposing the second inner wall surface. The second body portion defines a second receiving surface and a second coupling surface and a second body peripheral surface. The first coupling surface of the first sash portion is coupled to the second coupling surface of the second sash portion. The integrated sash unit also includes a first glazing panel supported by and coupled to the first inner wall surface of the first sash portion without being coupled to the second sash portion and a second glazing panel supported by and coupled to the second inner wall surface of the second sash portion without being coupled to the first sash portion.

An integrated sash unit including a first sash portion. The first sash portion a first body portion and a first receiving wall extending inwardly from the first body portion. The first receiving wall has a first inner wall surface and a first peripheral wall surface opposing the first inner wall surface. The first body portion defines a first receiving surface and a first coupling surface and a first body peripheral surface opposite the first receiving surface and the first coupling surface. The integrated sash unit also includes a second sash portion forming a second body portion and a second receiving wall extending inwardly from the second body portion. The second receiving wall has a second inner wall surface and a second peripheral wall surface opposing the second inner wall surface. The second body portion defines a second receiving surface and a second coupling surface and a second body peripheral surface. The first coupling surface of the first sash portion is coupled to the second coupling surface of the second sash portion. The integrated sash unit also includes a first glazing panel supported by and coupled to the first inner wall surface of the first sash portion without being coupled to the second sash portion and a second glazing panel supported by and coupled to the second inner wall surface of the second sash portion without being coupled to the first sash portion.

A heat-insulating window panel includes: a light-transmissive member having light transmissivity; and a panel member including an outdoor substrate that supports the light-transmissive member from an outdoor side via a first elastic body, an indoor substrate that supports the light-transmissive member from an indoor side via a second elastic body without being in contact with the outdoor substrate, and a heat-insulating material disposed between the outdoor substrate and the indoor substrate, and even when a force is applied to one of the outdoor substrate and the indoor substrate in a direction away from the other to move the one in a separating direction, the outdoor substrate and the indoor substrate have a hooking margin for hooking the one on the other.

A heat-insulating window panel includes: a light-transmissive member having light transmissivity; and a panel member including an outdoor substrate that supports the light-transmissive member from an outdoor side via a first elastic body, an indoor substrate that supports the light-transmissive member from an indoor side via a second elastic body without being in contact with the outdoor substrate, and a heat-insulating material disposed between the outdoor substrate and the indoor substrate, and even when a force is applied to one of the outdoor substrate and the indoor substrate in a direction away from the other to move the one in a separating direction, the outdoor substrate and the indoor substrate have a hooking margin for hooking the one on the other.

An adjustable header having a first header piece and a second header piece, which are attachable to each other by a connector.