Fact of the Matter: Windows

By C. G. Hoffman

"The history of architecture is also the history of windows" said Le Corbusier, the Swiss-French pioneer of modern architecture.  

• Windows serve two main purposes: to let in light and to let in air. For much of human history, a window was simply a hole in either the wall or the ceiling, there for lighting and to let air in or smoke out. Although the seemingly miraculous material made from melted sand had been known for thousands of years, and Roman craftsmen were experts at blowing beautiful glass vessels, their use for windows was unknown. A window (usually only one per dwelling) was most commonly a hole in the wall, and it was covered with wooden shutters when it got too cold.

• In ancient China and Japan, windows were covered in thin sheets of translucent paper, which let in the light.

• In medieval Europe, glass was a very expensive commodity. Some windows were covered in thin sheets of animal horn, sliced thin enough that it would let in a small amount of light. Medieval churches became famous for their stained glass windows, which were fabricated using molten lead to frame tiny spaces, which were then filled in with crushed, melted glass colored with various metals. These stained glass windows served an important purpose: Not only was almost everybody illiterate, but the Catholic Church actually didn’t want people to read the bible! They wanted to control the narrative to depict approved images of bible stories on the windows.

• When most people think of medieval times, they think of knights, heroic tales, and grand castles. But castle living wasn’t so grand, after all. Medieval castles were built for protection, not for comfort. They were mostly built of stone and were cold and drafty. They had a specific type of window called arrowslits or loopholes. They were narrow, vertical openings in the walls, which provided light and ventilation but also allowed archers to shoot arrows from inside the castle at approaching enemies.

• Glass produced in medieval times was thick, wavy, and uneven. It let in just a bit of light and didn’t allow for much of a view. By the 1500’s, glassmaking had advanced. Glassblowers would blow a long, balloon-like cylinder, which would then be reheated and pressed somewhat flat. Plate glass was invented in 17th century France and involved a lengthy process of pouring molten glass into molds, pressing it, and polishing it. Windows were commonly made of multiple panes, which could hold small sheets of glass. Glass windows were still exorbitantly expensive, and some aristocratic folks would take down their windows and bring them along on their travels!

• The Crystal Palace, built in Hyde Park, London, stunned visitors to the Great Exhibition of 1851. Made to showcase technological advances, it featured 60,000 panes of glass and astonished viewers with its clear walls and ceilings, which did not require any interior lights. It was considered such an architectural wonder that it was dismantled after the Great Exhibition and rebuilt in another part of London, where it stood until it was destroyed by fire in 1936.

• The invention of float glass in the 1950’s revolutionized the glass industry. It made possible the production of huge sheets of glass and led to the rise of enormous, glass-fronted skyscrapers. Today, windows continue to evolve, from self-cleaning windows to windows that block UVA and UVB rays to windows that provide superior insulation.

• The average US home has about eight windows. The White House, on the other hand, has 147. This is no match for Buckingham Palace, which boasts a whopping 760 windows. The Empire State Building is 102 stories high and has 6,500 windows. That’s all small potatoes compared to the world’s largest building, the Burj Khalifa, which has an astounding 34,348 windows!