Technically speaking, the first windows appeared about one thousand years BC and were nothing more than holes in the walls to permit air circulation and shed some natural light inside. The Romans were the first builders to place glass in window openings.
Those first panes were thick, blue-green in colour and full of tiny bubbles and impurities but were a major improvement for their time.
During the Middle Ages, glass windows and stained glass were used in churches as an art form to tell the story of the Bible and create a sense of awe and wonder for parishioners. Glass was very expensive and the lords and other members of the privileged ruling class used it sparingly because windows were favourite targets for flaming arrows and catapulted rocks during times of war.
It wasn’t until the Renaissance period that glass became more widely available and affordable for use in all types of building. These first modern windows were single panes of glass in a variety of sizes.
In the mid 1800’s a patent was taken out for the design of the first double glazed unit consisting of two panes of glass separated by a spacer with the air between the layers of glass acting as an insulation medium. Surprisingly most windows remained single pane, with or without storm windows, until well into the 1960’s and double glazing didn’t become popular until the later half of the 1970’s. No doubt as a result of the oil embargo and the resultant jump in home heating costs.
Since then many advances have been made in glazing and window components and today’s windows combine many sciences and technologies to the point where high performance windows can actually add a net heat gain to a building’s interior, rather than being a source of heat loss.
With many new and exciting developments in window technology on the horizon, the future of windows is bright indeed.