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About Insulated Glass Unit (IGU) Windows

A Glass Doctor Specialist in front of a window

What’s the definition of “IGU window,” and how can you tell if you have them? The experts at Glass Doctor are sharing the full IGU meaning, benefits of insulated glass units and why you should consider upgrading to this type of window if you haven’t already.

IGU Meaning

IGU is an acronym for “insulated glass unit,” which refers to double- or triple-pane windows with multiple panes of glass that range from 1/8-inch to 3/8-inch thick. The panes are separated by a spacer and sealed to prevent condensation buildup, and they are can also be filled with a noble gas such as argon.

How to Tell If You Have IGU Windows

Depending on the lighting, a quick glance at your window may reveal if it has a double- or triple-pane structure. If not, here are the steps to see if your windows are IGUs:

  • Light a match and hold it next to the glass. Make sure you don’t get too close.
  • View the reflection in the glass.
    • If you see a single reflection of the flame, it is single-pane glass, which means your window is not an IGU.
    • If there is a double reflection, your window has double-pane glass and is an IGU.
    • And a triple reflection means you have triple-pane glass and your window is an IGU.

The History of Insulated Glass Units

Invented and patented in 1865 by Thomas Stetson, insulated glass saw little use until the 1930s, when C.D. Haven made it commercially available as Thermopane. Building architects then began replacing the single-glazed (aka single-pane) windows of skyscrapers with double-glazed IGUs and incorporating green-tinted, iron-rich glass for occupant comfort. Later, the energy crisis of the 1970s pushed the U.S. government into further research to combat the loss of energy from the nation’s windows.

What Is Insulated Glass in an IGU?

Since glass is a poor insulator by nature, thickness doesn’t matter – but spacing between panes does. Seemingly innocuous, the air pockets (sometimes gas-filled) between triple- and double-pane glass panels boost insulating power, inhibiting heat transfer. Add a low-E coating, and you’re packing some serious insulating punch.

Benefits of Insulated Glass Units in Your Home

In addition to guarding against heat loss or gain, IGU windows have benefits beyond energy efficiency. Insulated glass unit windows also…

  • Increase comfort
    Making winter window drafts and air leakage a thing of the past.
  • Reduce sound transmission
    A boon in homes near busy streets or with noisy neighbors.
  • Boost window strength
    Standing up against strong winds (and overzealous children).
  • Lower heating and cooling bills
    By upholding the thermal envelope of your home to keep heat where it’s supposed to be.

Insulated Glass Unit Replacement and More from Glass Doctor

With customizable shapes, sizes and thicknesses, insulating glass units offer a greener, cleaner window solution for every application, from industrial to commercial and residential. Your local Glass Doctor can provide everything from IGU installation to window repair. Schedule an appointment online today to get started.