HISTORY : Need for Light and Air Inside Opens a Window on Architectural Details

Windows, depicted in wall paintings of ancient Egyptians, are as old as homes. Even prehistoric peoples made holes in the roofs of their huts to provide ventilation and light.

Indeed, the word “window” is derived from one of these functions, from the old Norse word, vindauga, made up of vind meaning wind and auga signifying eye. As early peoples devised other ways to remove smoke from their homes, such as through clay pipes, windows became prominent in the walls of homes instead of roofs. Animal skins, shells and scales of large fish were used as window coverings.

In ancient Greece, skylights were employed, often covered with mica sheets or thin slabs of translucent marble. Ancient Rome was the first civilization to have glass windows. It discovered the technology of mixing sand and other component materials and heating the mixture so it could be pressed and cast into small pieces that were formed into panes.

But this was a risky, costly and time-consuming process, and the homes of the wealthy were likely to be the only ones with glass windows. Nor was the quality high, with glass often marred by bubbles.

In medieval Europe, the huge size of Gothic architecture induced artisans to try other methods to make and install glass windows. Church windows were so large that a single pane of glass could not be used; instead, stained and painted glass in small pieces set in lead strips were fashioned into immense window designs towering skyward.

But the decorative technology was less appropriate for medieval castles, whose owners had to worry about military attacks in which glass windows were liabilities. Thus, shutters were often used to close windows in the homes of the wealthy.

By the 15th Century, glass made its entry, usually on the upper part of a window, with shutters on the lower. But the glass remained in small panes because of the continued difficulty of making large sheets of glass of uniform thickness. Nor were glass windows affordable to common folk, who were forced to employ less-costly translucent materials, such as oiled paper.

Also by the 15th Century, architects began to consider the function of windows in a structure. Hence the rise of fenestration, or balancing windows to wall areas based on the theory that a building with too many windows was unstable.

By the 16th Century, casement windows (hinged at the side and swinging in and out) prevailed in much of Europe, with France’s casement model extending to the floor and opening like folding doors. And for France’s steep roofs, the dormer window to provide light to attics became widespread. In England, and later America, the double-hung window--two frames of equal size that slide up and down--prevailed.

To be sure, greater efficiency in glassmaking contributed to making these movements possible. By the 1700s, glass windows became the rule as the price was reduced. But it was a slow process: A window that required 24 panes in 1750 might have only six half a century later. It wasn’t until the Industrial Revolution in the late 19th Century that the machine-cylinder method of production made glass windows affordable for large numbers of people.

In the U.S., Sears, Roebuck & Co. could advertise in its 1897 catalogue a double-hung window measuring as large as 24 by 38 inches with a price tag of only 55 cents.