All You Need to Know About Different Types of Window Glass

Like it’s not enough that you have to choose from six or more different types of windows when it’s time to replace the old ones.

Now you have several options for the glass that goes into those windows

Until relatively recently, no one had this problem. Every window came with a single pane of the same type of glass. It’s called float glass; Sir Alastair Pilkington developed it in the late 1950s, and it is still the basis for most of the glass used in Canadian residential windows today.

In the last few decades, glass manufacturers have developed annealed (treated to improve its strength) float glass in an effort to increase its insulation factor, solar reflectivity and to introduce new features, like self-cleaning properties.

The result is homeowners face a growing variety of window glass features and benefits to choose from when replacing their windows.

• Tempered Glass – Treated with extreme heat and rapid cooling, tempered glass is four times as strong as annealed glass.
• Laminated Glass – Laminated glass is a safety glass that is fused with layers of clear vinyl, which holds pieces off the glass together if it is broken.
• Insulated Glass Units (IGU) – Also known as double- or triple-glazing, IGUs are made of two or more panes of glass separated by a spacer. The spacing between the glass increases the insulating capacity of the IGU beyond that of simply the two pieces of glass placed together. The insulating capacity is increased further by adding different gases, including argon, to the space.
• Low-Emissivity Glass – Commercially known as LoE glass, it has a special coating, usually tin or silver, that reflects infrared light, but allows visible light to pass through. That means infrared heat from the sun is reflected away from the building in summer, keeping it cooler. In winter, infrared heat already in a building is reflected back into the building, keeping it warmer.

But knowing the different types of glass doesn’t mean you know all your options. Each type of glass can be further treated to make it suitable for different uses. For example, LoE glass can be coated with an opaque layer so bathroom windows can offer privacy.