Low-E Glass Explained: How It Saves You Money in Illinois

You've seen "Low-E glass" mentioned in every window brochure, but what does it actually do and why does it matter in Illinois? Here's the clear explanation.

What Low-E Means

Low-E stands for "low emissivity." It refers to a microscopically thin metallic coating applied to the glass surface that reflects certain wavelengths of energy. The coating is invisible to the naked eye — you can't see it or feel it on the glass.

How It Works in Winter

In winter, Low-E coating reflects heat (infrared radiation) from your heating system back INTO your home instead of letting it escape through the glass. Your furnace heats the room, that heat hits the window glass, and instead of passing through to the cold outside, the Low-E coating bounces it back inside. Result: your home stays warmer with less heating energy.

How It Works in Summer

In summer, the same coating reflects the sun's heat (solar radiation) AWAY from your home before it enters through the glass. The sun beats down on your windows, and instead of turning your rooms into a greenhouse, the Low-E coating blocks a significant percentage of solar heat gain. Result: your AC works less hard and your rooms stay cooler.

Low-E + Argon Gas + Triple-Pane

The combination of Low-E coating, argon gas fill between panes, and triple-pane construction creates the highest-performing glass package available. Each technology addresses a different type of energy transfer: Low-E handles radiation, argon gas reduces convection, and the triple-pane configuration reduces conduction. Together, they cut energy loss through windows by 25-40%. Are triple-pane windows worth it? →

All of the Andersen windows we install include Low-E glass as standard. Learn about our window installation →