If you look around at the houses in your town or city you will see double glazing on almost all of them. In fact we probably take double glazing for granted, even though it has only been in existence for around 60 years. That makes it a relatively new innovation in glass and a significant step in the design of our homes. So where did it all start and what might we expect as we enter the next decades of glass production?
After watching a plate float in the sink, Alastair Pilkington developed his idea for a flatter and more uniform glass – now known as Pilkington glass. His method of floating the molten glass over a metal form (much like water over the plate in his sink) allowed for the future of double glazing and more importantly the films that make the glass more energy efficient.
The first examples of two panes of glass within a casing appeared – known as Thermopane – these featured a simple construction of two panes of glass with an air gap between that were welded together.
This welded glass was now very common but the space between the glass panes had been increased and rubber spaces included to reduce the stress on the metal frames. It was about this time that vinyl windows started to be seen. Introduced by Thermal Industries in the US, these vinyl windows were offered as replacement window options, however the idea didn’t take off until the 80’s.
By the end of the 60’s clad windows became more popular. These were metal or wooden windows that were clad in vinyl. This allowed for a traditional wooden look on the inside of the home and a more durable vinyl finish outside.
The design the window unit now started to be considered and tilt windows became popular. These windows allowed for easy cleaning and were perfect for upper floors. Introduced by Polytex, these were double hung tilt windows and were perfect for replacing older sash windows.
It was now that the design of the window became important with the development of round top windows. These allowed for historical designs to be replaced and for more modern and innovative house design. It was also at this time that new glass developments such as Low-e glass and gas filled double glazing came into existence. This revolutionised energy efficiency and improved the durability of the double glazed units.
The development of impact windows took place following the damage caused by a hurricane in the US. These windows are less used in the UK, but are designed to withstand high wind levels and used laminated glass and heavy duty frames to ensure they can withstand high wind levels.
Composite vinyl frames were developed during the 90’s in response to the contractions and stress that can be put on the UPVC. Using a fibreglass material, these frames have three times the strength of wood and eight times that of vinyl.
The 2000’s and beyond
Now the emphasis is on solar gain and energy efficiency as well as flexibility of size and shape. Glass is being developed that will act as solar panels while remaining transparent. Additionally windows that can be programmed, that have internal blinds and that can even switch to being opaque due to LCD technology have been developed.