What Causes Discoloration in Double-Pane Windows?

While not a common problem, discoloration can happen to double-pane windows. And as window replacement contractors, we often get asked how to fix it. In today’s post Renewal by Andersen® of Wyoming takes a look at what causes discoloration, and whether it can be fixed.

How Does Double-Pane Glass Work?

To understand why discoloration happens, and why only on windows with multiple panes, let us first take a look at how they work.

Since windows are a part of a building’s exterior, they need to have insulation. Other components — the roof, exterior walls, flooring — are insulated using expanding foam, fiberglass rolls or recycled paper. What these materials have in common is they’re opaque, which means they are not suitable for windows. Traditional windows are made with single panes of glass, enabling thermal transfer between indoor and outdoor spaces. This is why old windows are typically drafty during the winter season, and uncomfortably hot during the summer season.

This is where double-pane glass comes in. Separating the interior and exterior surfaces of the glass panes adds a layer of air that serves as insulation. The gap is a vacuum, therefore, there are far fewer molecules for heat to move through. The gap can be optionally filled with a harmless insulating gas to further improve insulation. It’s proven to be so effective that our own High Performance™ Low-E4® glass has double panes as a standard feature.

What Causes Window Discoloration?

Like any other type of window glass, double-pane glass is made for continued exposure to the elements. However, if moisture infiltrates the gap between the indoor and outdoor panes, the moisture can form noticeably dark-colored streaks within, which cannot be wiped off. Fortunately, discoloration is preventable by maintaining indoor humidity levels (the ideal levels are at about 30% to 50%) and by taking steps to prevent impact damage to the indoor side of the windows.

But what do I do with my discolored windows, you ask. Discoloration is not reversible, unfortunately. If your windows still have warranty coverage, you may be eligible for a glass replacement. If not, the best solution is to replace them with more durable ones. While it is possible to keep your old, discolored windows, its insulating capacity won’t be better than traditional single-pane ones.

Renewal by Andersen of Wyoming offers a wide selection of custom replacement windows. To learn more, give us a call at (307) 472-2199, or fill out our contact form to schedule a free consultation. We serve Laramie and Cheyenne, WY, as well as the surrounding communities.