A condensation-free window without seal failure.
A properly working window should be clear and free of condensation

A window seal has usually failed when you see fogging, hazing or the presence of moisture between panes of glass. Sealed units such as dualpane or tripane windows are meant to remain impregnable. But sometimes seals fail, like when a painter uses a heat gun or a homeowner uses a pressure washer too close to a window. Old windows are the most common reason for seal failure.

How do I fix Seal Failure? 

First, determine if you have a failed seal. Clean the inside and outside surfaces of your window to make sure you’re not looking at external moisture on the window. Also make sure the glass itself isn’t scratched or hazed because of an imperfection in the glass. Once you’ve confirmed the moisture is between the panes, you have several options:

  • You can call a glazier (glass specialist) to fix just the glass part of your window.
  • You can try to fix only the seal by calling in a specialist who can install a valve and seal and then expel accumulated condensation until the inside space is dry.
  • If you live in a mild climate, you may choose to do nothing, since a failed window seal will have little impact on your heating or cooling bills.
  • You might find the only option is to replace the faulty window, depending on the age of your window and the type and seriousness of the seal failure.

 FAQ Friday is a weekly feature where we answer Frequently Asked Questions about our products, service or industry. To see other FAQs we’ve answered, visit our FAQ page. If you have a question you don’t see an answer for, just ask in a comment or contact us.


  1. Dennis Lane


    I have 5 jeldwen windows on the top floor of my house and all 5 have at least one window pane with moisture in between. How do I fix this?


  2. We have Jeld-Wenn windows in our house as well, installed by the builder. All the windows upstairs have condensation between the panes. I could understand one window, but all of them? Clearly there is a manufacturing defect but, unfortunately, the house is four years old so the windows are out of warranty.

  3. Steve arklie

    Installed jeld wen windows as soon as the warranty was up every sealed unit started to go.

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