|Window Sashes for Replacement Windows|
|The window sash fits into the window frame. The type of sash determines how the window will operate|
When people discuss the various window styles they are referring to the type of window sash which sits within the window frame and how that sash operates.
 Window Sash
Windows are available as either fixed windows or opening windows in which the sash shifts to open or close the window. The sash is a unit assembly of rails and stiles which hold the glass within a sash frame. Sashes are set in the window frame and operate by sliding vertically or horizontally on a track or swinging inward or outward on hinges. Sashes seal against the window frame tightly to prevent air leakage or weather penetration, though if the seal is too tight, the window will not operate correctly.
 Sashes Styles
 Hinged Sashes
Hinged sashes are generally hinged on one side of the sash. These hinges then attach to their partner hinges which are mounted on the window's frame. The hinges allow the sash to swing open like a door. Hinged windows provide the best seal and have the lowest air leakage for an operating window.
 Butt Hinge Sash Window Styles
Butt hinged sash styles include casement windows in which the sash is hinged on the side of the window and swings the sash inward or outward, hopper windows in which the sash is hinged on the bottom of the window to open it inwardly or outwardly and awning windows in which the sash is hinged on the top of the window, enabling it to open into or out of the house.
 Pivot, Garden and Tilt Turn Sash Window Styles
Additional hinged windows include garden windows which shift in and out using garden window arm hinges, pivot windows which pivot up to 360 degrees on pivot hinges and tilt and turn windows which either swing open from the side or bottom or pivot to open from the middle.
 Sliding Sashes
Window sashes may also slide or glide within the window frame. These sashes shift either side-to-side, in a horizontal sliding window, or up and down, in a vertical sliding window.
 Component Parts of an Operable Sash Window
In order for a sash to work properly the window installer must ensure that the component parts function properly.
 Cranks and Handles
The opening handle or crank is installed on the window sash. These hardware pieces are available in a variety of materials including hard plastic, brass and bronze. An attractive crank or handle adds a focal point of architectural interest to a window.
Weatherstripping is used to seal the space between a window frame and an operable sash. The weatherstripping seals the window and prevents air leakage. It is an important component of the window and should be replaced immediately if it cracks or tears.
 Spacer Bars
If the sash is a double pane or a triple pane sash, it will include spacer bars. They can be seen around the perimeter of the glazing unit and separate the panes of glass which are sealed into the sash. They are generally made from aluminum and the addition of a warmedge spacer will increase the sash's energy efficiency on a fiberglass, wood, wood clad, vinyl or composite window frame. The spacer bars absorb moisture from the air or gas that is trapped between the panes of a multi-pane window. This prevents condensation or fogging.
The bottom rail of the top sash and the top rail of the bottom sash are the meeting rails of a window sash.
The side bars of the sash are the sash-stiles.
The inside lining holds the glazing in the sash from the interior of the sash. It is located right adjacent to the glazing unit. The outside lining surrounds the sash including the glazing, rails and stiles.
Window sashes may include single pane glazing, double pane glazing or triple pane glazing. The desired level of glazing will depend on the desired level of thermal performance. Energy experts suggest that individuals who live in extreme climates buy window with triple pane glazing sashes.
The glazing may also include a low-emissivity anti-sun coating which blocks solar heat gain.