When you go to “open the window,” it’s the window sash you’re working with. As the operable portion of your window, the window sash houses and protects the window’s insulated glazing unit (IGU), and moves in one direction inside the window frame: vertically for double-hung windows, horizontally for sliders, or on a hinge in the case of crank-out windows like casements or awnings.
This movement is important. Window sashes need to stay square and true in order to properly seat within the window frame for a tight seal against drafts and energy loss. Unlike sashes in other vinyl windows, the C-Core Reinforced Sash in Improveit’s Performax54 windows features rigid construction so you’ll never have to worry that your window sash will warp, bow, or move in any other direction than it’s intended to.