How to Spot Seal Failure

Single pane windows were normal for hundreds of years.  Now, it is rare to find a window that is not sealed.  Double- and triple-pane windows are composed of two or three panes of glass within an air-tight frame; in other words, they are sealed.  When this seal fails, they are less effective as weather barriers. But how do you know that the seal has failed?

When Failure Is An Option

Windows are subjected to the same brutal elements as are roofing and siding.  Yet roofing and siding are hardy materials; windows are delicately constructed devices with moving parts.  The element that forms the core of windows is the Insulated Glass Unit, or IGU.

While failure is not intentionally built into IGUs, it is not unexpected.  This is the secret that window manufacturers do not include in their sales literature.

It is not uncommon for a house to have at least one window with a failed seal.  The cause can either be an immediate, outright failure of the seal or a slow, expected leakage over time.

Even in climates that are not considered extreme, it is common to find double-pane, sealed IGUs. The reason they are sealed so tightly is because they have an air vacuum between the panes.  Sometimes this air vacuum is replaced with a low conductivity inert gas like argon or krypton.

It is this very combination of two and even three sheets of glass and the gas within which keep the cold away.

Detection Tips

  • Clean Them First:  Since your test is all visual, you need to provide yourself with a blank slate.  Thoroughly clean both the inside and the outside of the window so you are certain that you are not looking at external moisture.
  • Moisture Within the IGU:  Fogging, hazing, or moisture between the two panes of glass mean that a window seal has failed. While a window can certainly fail and not have any moisture between the two panes, it is more common to see moisture between the two panes.
  • Glass Distortion:  This test is easier to see with larger sheets of glass.  PPG notes that as the krypton or argon gas leaks out, "air doesn’t backfill into the IGU [and] the two lights of glass begin to collapse into the center of the unit, which can cause the glass to look distorted or even break."  By standing at a distance outside and looking at the reflection, you can see if the glass is more distorted than windows that are not affected.
  • Save Those Warranties:  If you are in the habit of tossing out warranties, this is one product where you want to keep this information.  Premature window seal failure is clearly a product failure, not a function of poor installation.

One certain way not to detect a failed window seal is by putting your hand on the glass.  Unless it is viciously cold--far below freezing--it is doubtful that the "feel test" will work.

If you notice any of these things, call Crystal Clear View Glass at 602-224-7900 for a free in - home consultation. We come out and look at the window and let you know how it can be fixed. We are always here for you, welcome to the Crystal Clear View Glass family!