Home » Renovation » Window Evolution: Styles From The 18th Century To Present Day


Windows have come a long way in the past 300 hundred years. While the form and purpose of a window, an opening in a wall designed to admit light into a structure, has remained basically the same, major advances in manufacturing and construction have improved the energy-efficiency of windows over the centuries.

The First Windows

Glass windows have been used since ancient times, but the expense of glass meant that most homes throughout history did not enjoy the benefits of glazed windows until the eighteenth century. Poorer households usually made do with a simple opening in the wall that was closed with a shutter. Oiled paper, animal hide and horn were also used to cover window openings in homes that could not afford glass. These materials are partially transparent and permit a small amount of light to pass through but are highly inefficient at preventing heat transfer.

Because glass was difficult to make and to transport over long distances, the earliest glass windows were constructed using small sections of glass. These early windows let in some daylight that allowed people to perform basic tasks indoors but were poorly sealed and often kept shuttered or curtained during cold weather. Modern insulating materials such as silicon and caulk were non-existent, and the spaces between the glass and frame were often stuffed with paper or fabric to prevent drafts.

Development of the Glass Window

As glass became more affordable during the late eighteenth century, homes were constructed with larger windows, but these still consisted of small panes set into frames. Modern windows imitate these older windows by using dividers, but modern windows are generally made from a single sheet of glass with the dividers on the outside rather than individual small panes set into a framework. Although an improvement over previous methods of window construction, these paned glass windows were not as energy-efficient as modern windows and afforded ample opportunity for air and moisture to pass through.

The Industrial Revolution revolutionized the way glass is made. Ever-larger and thinner sheets of glass were produced using new rolling processes, and new formulas improved the quality of the glass itself. Better methods of packing and transportation, including improved roads, also allowed glass to be shipped longer distances. Picture windows became popular in the nineteenth century. So named because they resembled a picture of whatever was immediately outside surrounded by a frame, picture windows, like all other windows of the time, were constructed with minimal insulation. Better methods of caulking were developed during the late nineteenth century and early twentieth century, but the materials used were prone to drying out which led to increasing heat and air loss from the building over time if the caulking was not reapplied on a regular basis.

Energy Efficient Windows

The post-World War II construction boom initiated many improvements in building materials, one of which was the creation of double-paned glass windows. Double-paned windows consist of two glass panels separated by a void space. This void space prevents the transfer of heat through the glass. Vinyl and other synthetic materials also replaced the traditional wood frame that tended to shrink or warp and that required frequent repainting and maintenance. Modern synthetic caulks also provide superior sealing compared to earlier insulating materials. Double-paned energy efficient windows allow homeowners to dramatically decrease their utility bills. Although the upfront cost may seem daunting, the amount of money and energy saved over the years will definitely pay off.

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Peter Wendt is a freelance writer and home builder living in Austin, Texas. With his new construction homes, Wendt always installs energy star rating high efficiency windows to help create an energy efficient home from the ground up.

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