What Causes Discoloration in Double-Pane Windows?

Double-pane windows help reduce your monthly energy consumption by limiting the amount of heat that passes through the glass. One of the most common problems associated with double-pane glass is discoloration. In this blog, window installation company Renewal by Andersen® of Louisville/Lexington discusses what causes this and how it can be fixed.

How Double-Pane Windows Work

Every home has an energy enclosure, which includes the attic, exterior walls and fenestrations such as the skylights, entry doors and windows. All these components are insulated: exterior walls may have fiberglass batt or expanding foam; the attic floor or roof deck may have loose-laid or blown-in insulation; and entry doors may have foam cores. An insulated environment should allow minimal heat transfer, which results in consistent indoor temperatures, a comfortable living space and energy savings.

Windows and patio doors are mostly made of glass, which happens to be a naturally conductive material. The insulation used in the other parts of the energy envelope is opaque, and therefore are not suitable for use on windows. The solution is double-pane glass. The space between interior and exterior surfaces dramatically reduces window conductivity. Set into an insulated sash or frame, you can choose any style from double hung windows to window walls and still enjoy the benefits of a fully insulated energy envelope. This has proven to be so effective that Renewal by Andersen replacement windows come standard with double-pane glass packages.

Double-Pane Window Discoloration

Discoloration is caused by excessive indoor moisture and may appear as black or dark-colored streaks on the glass. The good news is that discoloration is preventable. You only need to make sure your home’s indoor humidity levels are within the ideal range. You can use a hygrometer (or your thermostat, if it’s equipped to detect relative indoor humidity) to ensure that indoor humidity levels do not exceed 55%. If humidity is a problem, use a standalone humidifier/dehumidifier, or have this technology integrated into your HVAC system.

Repair or Replace?

If your windows already have discolored glass, check your warranty, especially if the windows are two years old or less. Depending on the extent of discoloration, it is possible to have the problem repaired. Since the window structure won’t likely be affected by glass discoloration, ask your contractor if insert window replacements are possible.

Renewal by Andersen of Louisville/Lexington is your leading provider of popular replacement window styles, including casement windows. Give us a call at (502) 716-7264 (Greater Louisville), (859) 629-4649 (Greater Lexington), and (270) 215-5825 (Evansville and Owensboro). You can also fill out our contact form to schedule an appointment.