Double glazing is an inspired and incredibly simple way to keep warm air in your home and works on the principle that since heat cannot travel in a vacuum, having a vacuum space between two separate sheets reduces the amount that heat can escape out of a closed window,
It worked on the same principle as the Dewar flask, which was invented in 1892 and became the earliest example of the modern-day Thermos.
James Dewar was performing experiments on palladium, which he wanted to store at a specific temperature to discover its specific heat capacity (how much energy is required to increase its temperature) and to do this stored the palladium in a rather unique device.
He created a brass chamber, which was then enclosed in a second chamber before removing the air between the two to create a vacuum seal that keeps the temperature stable.
This principle was later used in the creation of thermopane, an early form of double glazing invented by C.D. Haven that used a central sealed air pocket between the two panes of glass that helps make the pane more energy efficient than a standard sheet of glass.
This system became very popular in the United States and would see further evolution when the air in the space between the glass panes was replaced with inert Argon gas, which due to its lack of heat conductivity reduces the amount of heat transferring between the two glass panes even further.
It would take over thirty years for the principle to reach the UK, as a global energy crisis affected the cost of heating and the arrival of cheaper double glazing saw an increase in popularity, and soon nearly every home in the country was experiencing a window and door replacement to fit the new technology.