window

 

in architecture, the casement or sash, fitted with glass, which closes an opening in the wall of a structure without excluding light and air. It may have a square, round, or pointed head; may be single, double, or grouped; in relation to the wall, it may be flush, recessed, or projected. A projected window is called a bay window if polygonal, a bow window if semicircular, an oriel if it has corbeled brick or stone supports. A mullioned window is divided by slender bars into panes; when the bars radiate from the center of a circular bar it is called a wheel. It takes the name of rose window when adorned with stained glass or figure design. The long, narrow window of the English Perpendicular Gothic church is called a lancet; a lunette fills a somewhat crescent-shaped space under a vaulted intersection high upon a wall. A fanlight, characteristic of the American Colonial style, is either a semicircular transom, usually over an entrance, or a small attic window (or often a pair flanking the chimney). A French window reaches the floor and has double casements opening as doors; originating in France in the late Renaissance, it was adopted throughout the Continent and in the Southern states in America. The double-hung sashes (sliding up and down within the frame), first used in Renaissance England, attained wide popularity. In Spain windows are frequently ornate, with stone framework, an elaborate head, and a decorative iron grille. In Indian and Byzantine windows a pierced slab of marble or alabaster often substitutes for glass. Muslims also used cement frames in which colored glass was set in brilliant arabesque forms. Carved and turned wood grilles are found in Syria and Egypt. In China and Japan, rice paper, protected by a sliding wooden shutter, often takes the place of glass. Shell, also used in China, was employed by the Romans, as were thin panes of marble, mica, and horn. In modern architecture the use of windows has greatly increased in dwellings and in the exterior walls of factories and commercial buildings.

It has been suggested that window frames be merged into this article or section. (Discuss)

A window is an opening in an otherwise solid and opaque surface that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material.

Etymology

The word Window originates from the Old Norse vindauga, from vindr "wind" and auga "eye." "Vindauga" is still used in Icelandic, as well as some Norwegian dialects to mean exactly the same thing: window. It is first recorded in the early 13th century, and originally referred to an unglazed hole in a roof. Window replaced the Old English eagþyrl, which literally means "eye-hole," and eagduru, "eye-door". Most Germanic languages however adopted the Latin word fenestra to describe a window with glass, such as Swedish fönster, or German Fenster. Notable exceptions to this, apart from English, are Danish and Norwegian, with the English word window closely resembling the words vindue and vindu respectively. This is probably due to the Scandinavian influence on the English language by means of loanwords during the Viking Age. In English the word fenester was used as a parallel until the mid-1700s and fenestration is still used to describe the arrangement of windows within a facade.

Definition and types of windows

A window is an opening in a wall that lets light and possibly air into the room and allows occupants to see out. Primitive windows were just holes. Later, they were covered with animal hide, cloth, or wood. Shutters that could be opened and closed came next. Over time, windows were built that both protected the inhabitants from the elements and transmitted light: mullioned glass windows, which joined multiple small pieces of glass with leading, paper windows, flattened pieces of translucent animal horn, and plates of thinly sliced marble. Mullioned glass windows were the windows of choice among European well-to-do, whereas paper windows were economical and widely used in ancient China and Japan. In England, glass became common in the windows of ordinary homes only in the early 17th century whereas windows made up of panes of flattened animal horn^{[citation needed]} were used as early as the 14th century in Northern Britain. Modern-style floor-to-ceiling windows became possible only after the industrial glass making process was perfected. Evidence of glass window panes in Italy dates back nearly 3000 years.

Modern windows are customarily large rectangles or squares with glass surfaces. Churches traditionally have stained glass windows.

Modern domestic windows come in many styles. The choice of design varies throughout the world, and is largely dictated by the prevailing weather conditions. Coastal climates tend to have smaller outward-opening windows due to the stronger winds experienced - e.g. England. Continental climates tend to have larger windows, many of which open inwards - e.g. France and Germany. Styles available include:

Double-hung sash window

The traditional style of window in the USA, and many other places that were formerly colonized by the UK, with two parts (sashes) that overlap slightly and slide up and down inside the frame. The two parts are not necessarily the same size. Nowadays, most new double-hung sash windows use spring balances to support the sashes, but traditionally, counterweights held in boxes either side of the window were used. These were and are attached to the sashes using pulleys of either braided cord or, later, purpose-made chain. Double-hung sash windows were traditionally often fitted with shutters. Sash windows may be fitted with simplex hinges which allow the window to be locked into hinges on one side, while the rope on the other side is detached, allowing the window to be opened for escape or cleaning.

Single-hung sash window

One sash is movable (usually the bottom one) and the other fixed. This is the earlier form of sliding sash window, and is obviously also cheaper.

Horizontal sliding sash window

Has two or more sashes that overlap slightly but slide horizontally within the frame. In the UK, these are sometimes called Yorkshire sash windows, presumably because of their traditional use in that county.

Casement window

A window with a hinged sash that swings in or out like a door comprising either a side-hung, top-hung, or occasionally bottom-hung sash or a combination of these types, sometimes with fixed panels on one or more sides of the sash. In the USA these are usually opened using a crank, but in Europe they tend to use projection friction stays and espagnolette locking. Formerly, plain hinges were used with a casement stay. Handing applies to casement windows to determine direction of swing.

A top hung hinged sash is also called an AWNING window.

Tilt and slide

A window (more usually a door-sized window) where the sash tilts inwards at the top and then slides horizontally behind the fixed pane.

Tilt and turn

A window which can either tilt inwards at the top, or can open inwards hinged at the side.

Transom window

A window above a door; if an exterior door the transom window is often fixed, if an interior door it can often open either by hinges at top or bottom, or can rotate about hinges at the middle of its sides. It provided ventilation before forced air heating and cooling.

Jalousie window

A window comprised of many slats of glass that open and close like a Venetian blind, usually using a crank. The hinges may be at the top or middle of each of the slats of glass. A Jalousie door is a door with a Jalousie window. These windows are used extensively in Australian tropical and subtropical architecture, particularly in Queensland, where they are known as louvred windows.

Clerestory window

A vertical window set in a roof structure or high in a wall, used for daylighting.

Skylight

Main article: Daylighting

A flat or sloped window built into a roof structure that is out of reach for daylighting and plant watering.

Roof Window

A sloped window built into a roof structure that is in reach for daylighting.

Roof Lantern or Cupola

Main article: Cupola

A roof lantern is a multi-paned glass structure, resembling a small building, built on a roof for day or moon light. Sometimes includes an additional clerestory. May also be called a cupola.

Bay window

A multi-panel window, with at least three panels set at different angles to create a protrusion from the wall line.

Oriel window

A window with many panels. It is most often seen in the typical Tudor-style house and monasterie. An oriel window projects from the wall and does not extend to the ground. Oriel windows originated as a form of porch. They are often supported by brackets or corbels. Buildings in the Gothic Revival style often have oriel windows.

Fixed window

A window that cannot be opened, whose function is limited to allowing light to enter. Clerestory windows are often fixed. Transom windows may be fixed or operable.

Picture window

A very large fixed window in a wall, typically without glazing bars, or glazed with only perfunctory glazing bars near the edge of the window. Picture windows are intended to provide an unimpeded view, as if framing a picture.

Multi-lit window

A window glazed with small panes of glass separated by wooden or lead "glazing bars", or "muntins", arranged in a decorative "glazing pattern" often dictated by the architectural style at use. Due to the historic unavailability of large panes of glass, this was the prevailing style of window until the beginning of the twentieth century, and is traditionally still used today.

Emergency exit window / egress window

A window big enough and low enough so that occupants can escape from the openable part in an emergency, such as a fire. In the United States, exact specifications for emergency windows in bedrooms are given in many building codes. Vehicles, such as buses and aircraft, frequently have emergency exit windows as well.

Stained glass window

Main article stained glass

A window composed of pieces of colored glass, transparent or opaque, frequently portraying persons or scenes. Typically the glass in these windows is separated by lead glazing bars. Stained glass windows were popular in Victorian houses and some Wrightian houses, and are especially common in churches.

Technical terms

Etymologically speaking, any window can be called a "light". However, within the window industry, particularly in insulated glass production, the term "lite" (so-spelled to keep the meaning differentiated from actual sunlight) is used to mean a single glass pane, several of which may be used to construct the final window product. For example, a sash unit, consisting of at least one sliding glass component, is typically composed of two lites, while a fixed window is composed of one lite. The terms "single-light", "double-light" etc refer to the number of these glass panes in a window.

In the USA, the term replacement window means a framed window designed to slip inside the original window frame from the inside after the old sashes are removed. In Europe, however, it usually means a complete window including a replacement outer frame.

The USA term new construction window means a window with a nailing fin designed to be inserted into a rough opening from the outside before applying siding and inside trim. A nailing fin is a projection on the outer frame of the window in the same plane as the glazing, which overlaps the prepared opening, and can thus be 'nailed' into place).

In the UK and Europe, windows in new-build houses are usually fixed with long screws into expanding plastic plugs in the brickwork. A gap of up to 13mm is left around all four sides, and filled with expanding polyurethane foam. This makes the window fixing weatherproof but allows for expansion due to heat.

Window materials

Modern windows, in developing countries in colder climates, typically have insulated glazing, called insulated glass when made from glass, which for insulated glazing is usually double paned but might be triple paned.

Modern windows are usually glazed with one large sheet of glass per sash, while windows in the past were glazed with multiple panes separated by "glazing bars", or "muntins", due to the unavailability of large sheets of glass. Today, glazing bars tend to be decorative, separating windows into small panes of glass even though larger panes of glass are available, generally in a pattern dictated by the architectural style at use. Glazing bars are typically wooden, but occasionally lead glazing bars soldered in place are used for more intricate glazing patterns.

Frames and sashes are traditionally made of wood, but metal, vinyl, and composites are also common. Solid metal frames and sashes are inefficient because metals conduct heat quickly. Whereas vinyl frames are inexpensive and relatively efficient, lack of durability becomes an issue. Some frames are made of vinyl-clad or aluminum-clad wood. Modern metal window parts typically consist of two surfaces separated by insulating spacer material.

A beam over the top of a window is known as the lintel or transom.

Many windows have movable window coverings such as blinds or curtains to keep out light, provide additional insulation, or ensure privacy.

Sun incidence angle

Historically, windows are designed with surfaces parallel to vertical building walls. Such a design allows considerable solar light and heat penetration due to the most commonly occurring incidence of sun angles. In passive solar building design, an extended eave is typically used to control the amount of solar light and heat entering the window(s).

An alternate method would be to calculate a more optimum angle for mounting windows which accounts for summer sun load minimization, with consideration of the actual latitude of the particular building. An example where this process has been implemented is the Dakin Building, Brisbane, California; much of the fenestration has been designed to reflect summer heat load and assist in preventing summer interior over-illumination and glare, by designing window canting to achieve a near 45 degree angle.

Windows and religion

The symbolism of windows plays a part in the customs and traditions of certain religions.

• In Christianity, the Gospel of Matthew mentions an ornate window in reference to the Last Supper. Protestants have used this window reference to support their claims that Catholic faith is ‘ornamental’ or otherwise a corruption of Christ’s message.^[1]

• On the holiday of Hanukkah it is customary to place the lighted menorah on a windowsill, preferably facing the street, so others can see it. This only occurs during a full moon which takes place once a month.^{[citation needed]}

• In Karaite Judaism, Bar Mitzvah boys stand at an east-facing window and recite a meaningful passage of their choosing from the Torah. ^[2]

See also

• Defenestration
• Equip´baie, windows International Exhibition.
• Insulated glazing
• G-value
• Porthole
• Window tax
• Shop window
• Replacement Windows

Gallery

A window can be a simple hole in a stone wall

Window - Budapest, Hungary

Stained glass skylight and window, Auckland Museum.

Stained Glass Window. San Albino Church, Mesilla Village, Las Cruces, New Mexico (January, 1985).

Notes

External links

• Roman Glass from Metropolitan Museum of Art
• History of Stained Glass
• http://freenet.buffalo.edu/bah/a/DCTNRY/c/casement.html
• http://www.fibertec.com/fiberStory.php?textsID=5nrm:F'nêt'vls:Veister

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