Select Page

One of the most important elements of any window is also the element that’s hardest to see: the glass. Most people never think too much about the glass in their windows–if it’s not broken, that is–but knowing about the type of glass in your windows can help you to better understand how it protects your home, how it can improve energy efficiency, and more. Take a look at the different types of window glass!

Float Glass

One of the most popular types of glass in America used to be plate glass, but within the past 50 years, it has been replaced float glass. The name refers to the process used to create this type of glass: Molten glass is poured into a container and allowed to “float” over a bed of molten tin, and eventually, the side facing up is polished with fire, and the entire window is allowed to cool at a specific rate (this cooling process is known as annealing) in order to relieve the glass of its internal stresses. The resulting piece of glass has smooth, parallel surfaces with consistent thickness, and it comes in both clear and tinted varieties.

Tempered Glass

After a piece of glass has been allowed to anneal–in other words, to cool at a specific rate–it can be further heated past its annealing point until it reaches 1200° Fahrenheit. The glass is then rapidly cooled, and this process allows the center of the glass to remain fluid for longer than the surface does, enabling tensile and compressive stresses to form across the piece of glass that result in it becoming up to four times stronger than regular annealed glass. For this reason, tempered glass is an ideal safety glass due to its strength, and if it shatters, it does so by breaking into granular pieces that reduce the risk of overall injury. Tempered glass is often used in car windows.

Low-E Glass

For anyone looking to improve the energy efficiency of their home, installing windows with low-e glass will help significantly. A low-e, or low-emissivity, coating is applied to the glass that blocks infrared light from entering your home while allowing visible light in. Reflecting infrared light away from your home prevents heating and cooling loss, which saves you money on your energy bills!

For more information on window glass, visit!