Sash window
Encyclopedia
Muntin
Muntin or Muntin bar is a strip of wood or metal separating and holding panes of glass in a window. Muntins are also called "glazing bars", "muntin bars", or "sash bars". Muntins can be found in doors, windows and furniture, typically in western styles of architecture...
s. Although any window with this style of glazing is technically "a sash", the term is used almost exclusively to refer to windows where the glazed panels are opened by sliding vertically, or horizontally in a style known as a "Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
light", sliding sash or sash and case (so called because the weights are concealed in a box case). The design of the sash window is attributed to the English scientist and inventor, Robert Hooke
Robert Hooke
Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...
. The oldest surviving examples of sash windows were installed in England in the 1670s, for example at Ham House.
The sash window is often found in Georgian
Georgian architecture
Georgian architecture is the name given in most English-speaking countries to the set of architectural styles current between 1720 and 1840. It is eponymous for the first four British monarchs of the House of Hanover—George I of Great Britain, George II of Great Britain, George III of the United...
and Victorian
Victorian architecture
The term Victorian architecture refers collectively to several architectural styles employed predominantly during the middle and late 19th century. The period that it indicates may slightly overlap the actual reign, 20 June 1837 – 22 January 1901, of Queen Victoria. This represents the British and...
houses, and the classic arrangement has three panes across by two up on each of two sashes, giving a "six over six" panel window, although this is by no means a fixed rule. Innumerable late Victorian and Edwardian
Edwardian period
The Edwardian era or Edwardian period in the United Kingdom is the period covering the reign of King Edward VII, 1901 to 1910.The death of Queen Victoria in January 1901 and the succession of her son Edward marked the end of the Victorian era...
suburb
Suburb
The word suburb mostly refers to a residential area, either existing as part of a city or as a separate residential community within commuting distance of a city . Some suburbs have a degree of administrative autonomy, and most have lower population density than inner city neighborhoods...
an houses were built in England using standard sash window units approximately 4 feet (1.2m) in width, but older, hand-made units could be of any size, as the image illustrates. It consists of an upper and lower sash that slide vertically in separate grooves in the side jambs or in full-width metal weatherstripping. This type of window provides a maximum face opening for ventilation of one-half the total window area. Each sash is provided with springs, balances, or compression weatherstripping to hold it in place in any location.
The name "hung sash window" is more usual in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and typically refers to a double hung window with two sashes that can move up and down in the window frame. A single hung window has two sashes but normally the top sash is fixed and only the bottom sash slides. Triple and quadruple hung windows are used for tall openings, common in New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
churches.
Construction is usually of softwood
Softwood
The term softwood is used to describe wood from trees that are known as gymnosperms.Conifers are an example. It may also be used to describe trees, which tend to be evergreen, notable exceptions being bald cypress and the larches....
, and units are generally single glazed; although double-glazed sashes are available it is more common for single-glazed sash windows to be replaced with top-hung casements when double glazing is retro-fitted. Some top-hung double-glazed units are manufactured to give the appearance of sashes.
Traditional problems with wooden sash windows include rot
ROT
The aviation term ROT stands for rate one turn, also known as a standard rate turn. All aircraft must be able to perform a standard rate turn....
, swelling or distortion of the woodwork, rattling in the wind (due to shrinkage of the wood), and problems brought on by careless application of paint. The sliding mechanism makes sash windows more vulnerable to these problems than traditional casement window
Casement window
A casement window is a window that is attached to its frame by one or more hinges. Casement windows are hinged at the side. A casement window (or casement) is a window that is attached to its frame by one or more hinges. Casement windows are hinged at the side. A casement window (or casement) is a...
s. Sash windows are relatively high maintenance, but offer advantages in return (looks, abides by laws (relating to older houses and buildings), natural resources etc). It is also possible to clean all the glass from within the building by sliding the two panes to different positions.
In recent years, uPVC sash windows have become available. These aim to replicate the aesthetic qualities of traditional sash windows, while overcoming many of the shortcomings - especially regular maintenance and painting, and energy inefficiency.
A significant advantage of sash windows is that they provide efficient cooling of interiors during warm weather. Opening both the top and bottom of a sash window by equal amounts allows warm air at the top of the room to escape, thus drawing relatively cool air from outside into the room through the bottom opening.