What Causes Moisture In Between Window Panes?

by | Sep 30, 2015 | Glass Repair, Glass Replacement, Insulated Glass, Residential Glass Replacement, Uncategorized

Double-pane windows, or insulated windows, are highly energy-efficient—able to lessen the amount of heat passing through their panes that are going into or out of homes. These windows are particularly useful during cold winter months. If your home has double-pane windows and you notice any condensation or fogging developing in between the panes, you should contact a professional who specializes in glass window repair in Houston . Moisture accumulating in between windows is an indication that your window’s seals have been compromised, and that they are allowing air to infiltrate the chamber between the glasses.

A skylight in a white building.

Thermal Pumping
Insulated windows are constructed with two panes of glass that are placed parallel to each other on a specialized frame. Inside the frame, and in between the glass panes, is a closed chamber that is sealed off and is usually surrounded by a desiccant (moisture-absorbing) strip. This space traps a layer of air—or gas, such as argon or krypton—which expands and contracts. When sunlight warms up the space, the air expands and creates pressure against the panes. When night falls, the air is cooled and contracts. Over time, these daily cycles, known as thermal or solar pumping, can stress the window’s glass’s seals, causing them to crack. Eventually, these cracks widen enough to allow air to enter the chamber. Water vapor in air condenses when it comes into contact with a relatively cold surface, producing moisture on the panes.

Window Failure
Windows located on walls that are not shaded from the sun, or where sunlight is strong, are susceptible to larger temperature fluctuations, which mean they experience more intense thermal pumping and a higher rate of failure. Window frames made of vinyl can experience greater thermal-expansion rates and long-term stress, which result in a higher rate of failure. Windows can also fail due to manufacturing defects.

Window Damage
If you neglect to address a moisture issue in between your double-pane window, you risk permanently damaging that window. Condensation can bead continuously on glass inside your window’s chamber, and those droplets run down the glass over and over, consequently etching grooves into its surface. In extreme cases, silica hazing can occur when a window’s desiccant becomes oversaturated and erodes. Silica particles can be carried by air moving through cracks in the seals, which can accumulate on glass surfaces and ruin them.