Single-Hung/Double Hung
In double-hung units, both sashes slide vertically. Only the bottom sash slides upward in a single-hung window. Ventilation area can vary from a small crack to an opening of one-half the total glass area. Screens can be placed on the exterior or interior of the window unit.
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Casement
Casement windows are hinged at the sides. Hinged windows such as casements generally have lower air leakage rates than sliding windows from the same manufacturer because the sash closes by pressing against the frame. Casement windows project outward, providing significantly better ventilation than sliders of equal size. Because the sash protrudes from the plane of the wall, it can be controlled to catch passing breezes, but screens must be placed on the interior side.
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Awning
Awning windows are hinged at the top and open outward. Hinged windows such as awnings generally have lower air leakage rates than sliding windows from the same manufacturer because the sash closes by pressing against the frame. Screens are placed on the interior of the window unit.
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Bay Window
A bay window is made up of three or more windows. The side or flanker units project out from the building in 30, 45, or 90 degree angles. The center is parallel with building wall and is made up of one or more windows. All the units can be stationary, operating, or any combination thereof.
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Bow Window
A series of four or more adjoining window units, commonly five in number, installed on a radius from the wall of the building.
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Fixed Frame
Refers to windows that are non-venting or inoperable.
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Slider
Both sashes slide horizontally in a double-sliding window. Only one sash slides in a single-sliding window. Ventilation area can vary from a small crack to an opening of one-half the total glass area. Screens can be placed on the exterior or interior of the window unit.
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