Casement

Casement windows are hinged at the sides. Hinged windows such as casements generally have lower air & water 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. Virtually the entire casement window area can be opened, while sliders are limited to less than half of the window area.

Single Hung and Double Hung

(Vertical Sliders)

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 of the window unit. Sliding windows, such as single- or double-hung units generally have higher air & water leakage rates than projecting or hinged windows.

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 of the window unit. Horizontally sliding windows generally have higher air & water leakage rates than projecting or hinged windows.

Awning

Awning windows are hinged at the top and open outward. Hinged windows such as awnings generally have lower air & water 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. Similar to casements, the entire window area can be opened, while sliders are limited to less than half of the window area.