Window operation is one of the most crucial choices to consider when selecting a window sash. Offering a variety of styles and functions applicable to specific conditions, a range of window operations should be considered to best meet your needs for ventilation, operability, screening, and daylighting. The primary difference between window operation types are between projected or hinged types such as casement, awning, and hopper windows and the sliding variety of windows that includes double-hung, single-hung, and sliding types. Other specialty types include pivoting, jalousie, skylights, and storm windows.
Casement windows are side-hinged with sashes that swing outward. Because of their outward rotation, casement windows provide significant direct ventilation and are often better suited for ventilation purposes compared to windows of equal size. Casements generally have lower rates of air leakage compared to sliding windows because the sash presses upon the frame when closing. Variations on the casement window include: interior screens to control breezes, tracks for the ends of the sashes to slide along as the window opens outward, and the option for a vertical mullion or a floating astragal connection for the sashes to close on.
Jalousie windows, or louver/louvre windows, is a window type with horizontal louvers set in a common frame with a track that allows for the user to simultaneously pivot the louvers. Because of this control, the jalousie window type can flexibly adjust airflow, light, and privacy with ease. Louvered windows have been commonly used in mild climates where operability can provide desirable ventilation during sun, rain, and cooler months. Variations include the possibility to vary louver widths and materiality, and also whether the window is operable (jalousie) or fixed (louver).
Ventilation: 100% max
Operation: Simultaneous pivot (jalousie), fixed (louver)
Variations: Louver dimensions, louver materiality, operable (jalousie) or fixed (louver)
Use: Mild climates; control ventilation or visibility
Jalousie Window front elevation, axon drawing
Double-hung windows have two or more sashes that slide vertically. Double-hung windows allow for both sashes to slide in separate tracks, while the single-sliding option only allows for one sash to slide while the other remains fixed. An advantage to slider windows is their ability to adjust ventilation from being totally open (50% max) to reducing air flow to a small opening. The sashes of a double-hung window remain held in place through the use of counterweights, friction, or pretensioned springs. Variations on the sliding window are: double or single tracks, screens on the interior or exterior unit, and the possibility of a pivoting hinge on the sash.
Sliding windows have two or more sashes that slide horizontally. Double-sliding windows allow for both sashes to slide, while the single-sliding option only allows for one sash to slide while the other remains fixed. An advantage to slider windows is their ability to adjust ventilation from being totally open (50% max) to reducing air flow to a small opening. Variations on the sliding window are: double or single tracks, screens on the interior or exterior unit, and the possibility of a pivoting hinge on the sash.
Fixed windows are comprised of a frame and a static sash. If paired with operable windows, the thickness of the fixed sash should best match the cross-sectional dimensions of the operable sash.