Window Operating Types
When selecting windows for your home, it's also important to consider how they're operated. Some operating types have lower air leakage rates than others, which will improve your home's energy efficiency.
There are numerous window operating types to consider. Traditional types include the following:
Awning
Hinged at the top and open outward. Because the sash closes by pressing against the frame, they generally have lower air leakage rates than sliding windows.
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Casement
Hinged at the sides. Like awning windows, they generally have lower air leakage rates than sliding windows because the sash closes by pressing against the frame.
Fixed
Fixed panes that don't open. They're airtight but not suitable in places where window ventilation is desired.
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Hopper
Hinged at the bottom and open inward. Like both awning and casement, they generally have lower air leakage rates because the sash closes by pressing against the frame.
Single- and double-hung
Both sashes slide vertically in a double-hung window. Only the bottom sash slides upward in a single-hung window. These sliding windows generally have higher air leakage rates than projecting or hinged windows.
Single- and double-sliding
Both sashes slide horizontally in a double-sliding window. Only one sash slides in a single-sliding window. Like single- and double-hung windows, they generally have higher air leakage rates than projecting or hinged windows.
