Unless you have an older home with single pane windows, it’s very likely your windows feature sealed glazing.  Also known as insulated glass units (IGUs,) glazed windows are prized for their insulative qualities.  They can keep a house cool when it’s hot outside and maintain indoor heat when it’s cold outside.  They can also reduce the transference of noise and ultraviolet sun rays.  It’s an inert gaseous layer between the panes of glass that give glazed windows these insulative properties.  However, over time, the seals that keep the gas in place are prone to failure.  How do window seals fail and how do you know if they have failed? These questions are the focus of this article.

 

How Do Window Seals Fail?

Typically, the failure of window seals is a slow and steady process.  The gas that occupies the space between the glass panes leaks out over time due to pressure differences between it and the air outside.  Even the best made glazed windows will eventually allow the gas to leak.  Major differences in air pressure, such as transportation through different elevations can speed up the leaking process.

 

How to Tell If Your Window Seals Have Failed

The most common symptom of seal failure in glazed windows is the presence of moisture or humidity between the panes of glass.  If your windows are fogging up, have droplets of condensation or exhibit traces of water that can’t be wiped away, it’s very likely that the window seal has failed.  Distortions in the view through your window can also be a telltale sign of seal failure.  This is due to the glass bending or warping from changes in pressure after the gas has leaked out.  

 

Solutions For Failed Window Seals

Although failed window seals are not a catastrophic event, aside from cloudy or foggy windows, the problem will reduce the insulative qualities of the windows.  This could lead to higher energy bills.  Depending on the climate and the cost of energy in your area, replacing the windows may be more expensive than living with them as is.  There are also methods of resealing the windows that can be employed without the need for replacing the frames.  This could also be a more cost effective way of dealing with the problem compared with overall replacement.