17 September 2018
How to Identify and Repair a Leaky Window Seal
How to Identify and Repair a Leaky Window Seal


Your home's windows....they connect you to the outside world, are sources of natural light and  help protect your home against the outside elements.  Unless you live in a very old home, most of your windows probably contain two or three panes of glass, with an open space between the panes.  The industry refers to them as IGUs (Insulated Glass Units) and they are designed to regulate the temperature in your home.   This is achieved by filling the glass panes with an inert gas, like argon or krypton, which are good insulators.  The gas is held in by an air-tight seal.  Unfortunately, some seals do fail.  Let's discuss the why's, how to detect and most importantly, getting them fixed.


Several things can contribute to a leaky seal:

·       The age of the window and how often it is used in the home.  

·       If you reside in a climate that experiences extreme temperatures or harsh weather. 

·       Mistakes made during installation or during the manufacturing process. 


If there is mold present in the panes, sometimes the homeowner can weaken the seal by using a heat gun to strip paint or cleaning with a power washer. Even the best windows experience a small gas leakage of about 1% a year. 


Detecting a leak will mostly come down to a visual examination of the window.  Start by, cleaning both sides of the window in question as to not mistake where you may be seeing moisture.  Look for fogging or a hazy appearance inside the panes.  A build-up of moisture is a clear indication that there is a problem.   For a larger window you may see a distortion of the glass itself.   On a sunny day, stand away from the window and view any reflection you see, if it seems distorted you may have a seal leak.


If you detect a questionable pane, your first step should be to check your warranty.  Call the place of purchase if you are unsure of coverage, they should be happy to work with you to resolve the problem. If your warranty has expired, inquire about pane replacement.   This repair can be intensive and is not recommended as a do-it-yourself project. 


Defogging is an option, but has received mixed reviews.   The procedure involves drilling a tiny hole into the glass, the condensation or fogging is expelled and then a valve and new seal is installed.  This fix does not really address the cause of the leak and may only last a short while.


It may seem odd, but choosing to do nothing is always an option.  Consider the harshness of the climate you live in.  Do you have extreme temperatures? Do you have more rain or snow fall than the average area?  Also, weigh the costs of replacing the window vs the increase in energy.   We would not recommend this for the long term. Proper home maintenance is essential to maintain your home’s value.


A little prevention goes a long way with maintaining your window seals.  Examine your windows several times a year, keep them clean and caulk any gaps you may find.  Go easy on the power washing and keep the heat gun away if you have paint stripping to do. Start off any window replacement project by purchasing quality windows from a trusted source.   Make sure that the windows are installed by workers that have been trained by the manufacturer or a professionally recognized training company.  Lastly, always check the warranty to see what coverage is offered.



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