Discoloration on Double Pane Glass: Causes and Prevention

Double pane windows can help you save on your energy bills thanks to its ability to reduce heat transfer between indoor and outdoor spaces. Discoloration is not a common problem, but it has been known to occur on some windows with double pane glass. In today’s post, replacement windows company Renewal by Andersen® of Central Pennsylvania shares a look at its causes and how it can be prevented.

How Do Double-Pane Windows Work?

To understand what causes discoloration on double pane windows, let us first take a look at its role in a system called an energy envelope:

The energy envelope is an enclosure that consists of the roof, exterior walls, and everything installed on them, including entry doors, windows, and skylights. Each of these components has to be insulated in order to prevent heat transfer, which can cause heat loss or heat gain depending on the season. Lack of insulation causes heating and cooling systems to increase their output to compensate for the temperature differences, resulting in higher energy bills.

Standard insulation materials like fiberglass wool, foam insulation, or recycled paper can be used on most other parts of the energy envelope. None of them can be used on windows because glass—a naturally conductive material—needs to stay transparent. This is where double-pane windows come in. The sealed airspace between two glass panels dramatically reduces heat conduction that works with all other parts of the energy envelope. It has proven to be so effective that all Renewal by Andersen® replacement windows feature double pane High Performance™ Low-E4® glass as a standard component.

What Causes Discoloration on Double Pane Windows?

The airspace between the glass panes is vacuum-sealed at the factory because the lack of air molecules within helps reduce heat conduction. It can also be filled with inert gases during manufacture, which enhances window insulation. If moisture infiltrates this space, it can result in dark-colored streaks that can’t be cleaned off.

Fortunately, it’s preventable. You can maintain relative indoor humidity levels to around 50% using a dehumidifier can help keep excess moisture from infiltrating window glass. You should also consider investing in quality replacement windows with limited warranties that include coverage for manufacturing issues that result in leaks.

Renewal by Andersen® of Central Pennsylvania is your leading provider of energy-efficient replacement windows in popular styles, including sliding windows. Give us a call at (717) 929-8610. You can also fill out our contact form to schedule an appointment. We serve Lancaster, PA, and the surrounding communities.