Part 1 of a 4 part series on home window origins, types, function, and fits. Part 1, a brief history of home windows.
Window: (noun): an opening in the wall or roof of a building or vehicle that is fitted with glass or other transparent material in a frame to admit light or air and allow people to see out.
“And what is more generous than a window?”
Windows – Our Transparent Bridge To Nature
Windows connect us with our outside world. They are the space we look through to be inspired. Their function is simple. Open or closed, depending on how we want our home to feel at any given time. Windows have come a long way over the millennia. They appear in various forms. Some use glass, some bamboo. Some are stained, some crystal clear.
Windows let in the sun and warm breezes or deter the heat and keep us cool and comfortable. They keep the frigid cold at bay, or permit gentle winds to pass through, allowing us to soak in the day.
Windows are constructed using a variety of materials. A person can create a window to be nearly any shape one can imagine. They can be as giant as an entire wall or as small as a peep hole.
Regardless of size, material, or color, windows are all built for two main functions. They protect us from the elements and simultaneously give us an inspiring view of our outside world.
Fun Fact: The English language-word window originates from the Old Norse vindauga, from vindr (“wind”) and auga (“eye”), i.e., “wind eye”. – Oxford American Dictionary (2010)
Windows originally represented the concept of an eye to the wind, a way to see our surroundings from a protected point of view, however rudimentary that opening may have been in the early days.
So let’s get to it! In this first article of our 4-part series, we’ll explore the origins and a brief history of windows. We’ll then move into modern manufacturing and give a breakdown of how the glass for windows is usually made in the present day.
The Beginning of Windows
So where did windows find their beginning? The word “window” was first recorded in the early 13th century, and originally referred to an unglazed hole in a roof. The earliest windows were unglazed openings in a roof to admit light during the day.
‘Later, windows were covered with animal hide, cloth, or wood. Shutters that could be opened and closed came next. Over time, windows were built to both protect the inhabitants from the elements and transmit light, using multiple small pieces of translucent material, such as flattened pieces of animal horn, thin slices of marble, or pieces of glass, set in frameworks of wood, iron or lead. In the Far East, paper was used to fill windows.
The Romans were the first known to use glass for windows, a technology likely first produced in Roman Egypt. Namely, in Alexandria around 100 AD cast glass windows, albeit with poor optical properties, began to appear, but these were small thick productions, little more than blown glass jars (cylindrical shapes) flattened out into sheets with circular patterns showing throughout. It would be over a millennium before a window glass became transparent enough to see through clearly, as we think of it now.
Over the centuries, techniques were developed to cut through one side of a blown glass cylinder and produce thinner rectangular window panes from the same amount of glass material. This gave rise to tall narrow windows, usually separated by a vertical support called a mullion.
Mullioned glass windows were the windows of choice among European well-to-do, whereas paper windows were economical and widely used in ancient China, Korea 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 were used as early as the 14th century.’ – Wikipedia
Windows Reach The Modern Age
Modern-style floor-to-ceiling windows didn’t become possible until after the industrial plate glass making processes were perfected. Most modern windows are usually filled with glass, although there are some made with transparent plastic. Also, the technology around creating the perfect window continues to become more sophisticated every day and some glass manufacturers are taking production to levels unimagined by the early pioneers of window making.
Most all glass windows are manufactured in factories. The process is intense, and temperatures often reach 1500 degrees Celsius during the procedure.
How The Glass For Windows Is Usually Made
We’ll give you a quick breakdown of what the window glass making process looks like.
- The materials required for making the glass are combined. These materials often include sand, soda ash, dolomite, limestone, salt cake and others.
- All of the materials are mixed together with what is called ‘surplus glass’ and heated in a furnace to 1500 degrees Celsius.
- Fun Fact: Most of these furnaces can hold more than 1200 tons of glass. Whoa.
- The glass melts and is brought to a temperature of 1200+ degrees Celsius.
- The glass is poured into a bath of molten tin. Tin is usually ideal for the glass-making procedure because it mixes very well with glass.
- The glass floats onto the tin surface, transforming into a sheet. The temperature is reduced, and the sheet is lifted onto rollers.
- Note: The differences in flow speed and roller speed create glass sheets of different thicknesses and widths.
- The glass is cooled and reheated slowly to increase strength and prevent shattering. Another method is tempering. The window glass is reheated and chilled with blasts of cold air.
- The glass may be glazed and coated with insulated window glazes, heat absorbing tints, or other coatings.
“There’s a world out there. Open a window and it’s there.”