Several other languages originating in Europe use a word based on wind when signifying window. Thus the Danish word is vindue and the Norwegian vindu. The Spanish for window is ventana, a word that comes from the Latin for wind, ventus. Other languages derive from the Latin for wind, fenestra; that word developed from the concept of a hole or opening. The Dutch say venster, the Germans fenster, the Swedes fönster, the Italians finestra, the French fenênetre. The Dutch also use the word raam which derives from frame or enclosure.
In the creation of residential or other structures builders frame buildings leaving appropriately located openings for windows. In modern practice windows are produced in factories and shipped to building sites in finished and ready-to-install units. In certain types of construction, particularly in high rise office buildings, the window takes the form of walls, not single units. The builder hangs specially fabricated curtain walls of glass from the building's metal frame. In residential applications windows come as units, usually in standard sizes. The builder orders special windows separately. A substantial portion of industry shipments are replacement windows purchased by homeowners. Windows are replaced for many reasons. The most important of these is energy conservation. People replace their windows because they want to save money and improve the appearance of their house. Replacing windows can reduce maintenance costs, provide better interior lighting, and change the entire appearance of a repainted house.
Sash, Frame, and More
Although windows appear to be quite simple products they are actually complex structures. Many an individual setting out to repair an old window put in place in the 1930s or 1940s has discovered the complexity in layers of disassembly and has gained respect for the producers of modern windows. The core element of a window is the sash, the frame that actually holds the glass. The sash may hold a single piece of glass or may be subdivided into multiple panes separated by grilles or so-called mutin bars. All sashes have a locking mechanism and either sliding rails or hinges depending on how they are to be opened. Fixed windows that cannot be opened are the exception. Movable sashes come in six varieties and windows are named after them: casement, single-hung, double-hung, sliders, awnings, and hoppers.
- Casement Windows. The sash is hinged at one side and opens outward. The sash may be moved by hand or may be activated by lever cranked by the user. When the sash is closed, one or more locks may be supplied to close it firmly.
- Single- or Double-Hung Windows. Such windows have two sashes arranged one above the other. In a single-hung window the upper is sash stationary whereas the lower can be opened, overlapping the upper sash. In the double-hung version, both sashes may be opened, the lower being raised, the upper being lowered. In old-fashioned designs the movement of the sashes was aided by weights (called balances) suspended on ropes running over a pulley, the entire arrangement hidden beneath the frame to either side. Modern windows use springs or compressible weather-stripping to keep the windows stationary.
- Sliders. These window work in a manner analogous to hung windows but may be opened by sliding them from side to side.
- Awnings Windows. The sash in this type of a window is hinged at or near the top and is intended to be opened outward. Levers hold the window open. Awnings are frequently crank-operated.
- Hoppers. The sash is hinged near or at the bottom and opens inward. Many single- and double-hung window sashes are also equipped with hinging at the bottom so that they may be opened inward for cleaning or outright removal. Hoppers, however, are designed for opening in that manner and no other. Fixed windows, the seventh type, are often used for decorative purposes. They may feature stained glass or be of unusual shape (arched, triangular, hexagonal, etc.), making them difficult to implement for opening except at unusually high cost.
Groupings of windows have special names. Bay windows form semi-circles. Transoms are windows set above doors, sidelights to either side of doors, and fanlights are arched windows above doors to throw light into an entry-way.
Sashes are also defined by the number of panes that they carry separated by mutin bars. If the sash carries more than one pane, the terminology used is upper over lower-each word applying to half the sash. Thus a 1/1 window has two panes, one over the other. A common type is 6/6, with six small panes on the upper level, six on the bottom. Other common types are 2/2, 4/4, and 9/6. Glass doors, and sometimes windows as well, feature 3/1 or 4/1, instances in which the upper half is subdivided into three or four narrow panes and a single large one forms the bottom. In some designs a window that appears to have multiple panes actually features but a single sheet of glass with mutin bars made of wood or plastic overlaid to give the appearance of multiple panes. In double-glazed windows fake and very thin mutin bars may be embedded between the panes of glass. The window looks subdivided, but in washing it the user can wipe over a single pane of glass.
