Discoloration in Double-Pane Windows: Causes and Prevention

Double-pane or insulated windows help you save on your energy costs by minimizing heat transfer between indoor and outdoor window surfaces. While not a common phenomenon, double-pane windows may show signs of discoloration. In this blog, replacement window and patio door installation company Renewal by Andersen® of Portland takes a look at the causes of window discoloration, and how it can be prevented.

How Double-Pane Windows Work

To understand how double-pane windows work, let us first take a look at how the energy envelope works. Every home has an enclosure comprised of the attic, exterior walls and fenestrations: entry doors, skylights, and windows. The enclosure is called the energy envelope, and when properly insulated, the enclosure should have consistent indoor temperatures. This results in a reduction in its indoor heating and cooling requirements, which, in turn, results in energy savings.

The attic and exterior walls are insulated using batt, foam or blown-in insulation. Replacement windows needed a different approach, as it is made of glass, which also happens to be a highly conductive material. The solution is double-pane glass. Separating the interior and exterior surfaces slows down heat conduction. When set into insulated frames, double-pane glass complements the rest of the energy envelope, helping improve the home’s energy efficiency. This has proven to be so efficient that all Renewal by Andersen replacement windows feature double-panel High Performance™ Low-E4® glass as a standard component.

Preventing Double-Pane Window Discoloration

Indoor moisture can cause discoloration on double-pane windows. It may appear as black or dark-colored streaks on the glass surface. Fortunately, window discoloration is preventable. You need to address moisture problems in your home, such as attic, kitchen and bathrooms with poor ventilation, incorrect humidifier/dehumidifier settings and improperly sized HVAC systems.

But what if you already have discolored windows? First, check the warranty coverage. Depending on the extent of the damage, you may be able to get it repaired under warranty. Should the windows require replacement, an insert window replacement—a replacement method where the original frame is kept intact—may help reduce the replacement costs.

Renewal by Andersen of Portland is your leading provider of replacement windows and patio doors. Give us a call at (503) 419-3960 or fill out our contact form. We serve customers in Portland and Wilsonville.