Big problems ahead for some vinyl windows? The picture may not be rosy.

A couple of years ago a window repair company did a presentation for a continuing education class I attended.  At the presentation the outrageous claim was made that an inordinate amount of premature failure of vinyl window seals was starting to happen.

The problem involved a particular type of spacer used to separate the panes of glass.

Being skeptical, I did a quick Google search of the issue and could find nothing.  All I could find was page after page of nothing but praise for the new technology of these spacers—called “warm edge” technology.  Even now, two years later, there is still scant information on the Internet regarding any issues with these spacers except for several hits for  the company making the claims that they are failing.

Since I too am seeing more failure of this type of seal than the old metal tube type spacer, I thought perhaps it was time to see what experience others were having related to this issue.  If nothing else it will result in my website showing up in the search results for the problem—along with the window repair company.

Typical spacers for windows have a life expectancy of about 25 years—-so failure of window seals happen.  It is just a matter of when.  In my opinion 25 years is too short of a time frame and part of the reason why replacing windows will never pay for themselves in terms of energy savings.  By the time they do, they will need replacement.  Of course the window hawkers are not going to tell you this.  Certainly if we have a particular component of double pane windows that is causing them to fail in less than 10 years we potentially have a huge problem.

Here is a little diagram that will attempt to show how these newer spacers, called “warm edge” spacers are different from conventional spacers and in theory better.  Truly, on paper they are genius, but in practice, apparently, not so much genius.  There are different styles depending on manufacturer and I will not attempt to discuss the different types.  It is possible that only one of the types is having this issue—and perhaps only one manufacturer.

How warm edge spacers work

How warm edge spacers work


Can you see how the edges of the blue channel that holds the glass “theoretically” flex with the curvature of the glass in the bottom two examples?

Basically all the spacers are is a channel filled with desiccant material.  Because the edges of the channel can flex with the glass, as the glass seasonally becomes convex or concave the seal should theoretically be more stable.  What is perhaps more perplexing is exactly “why” the theory does not seem to be holding up under “practice.”

In the following pictures you can see the effect of the sun on the South windows of a home that is only 10 years old. 

Slumping Desiccant material---things are not looking rosey

Slumping Desiccant material—things are not looking rosy

Slumping Desiccant in the side channel

Slumping Desiccant in the side channel

Slumping desiccant in a side channel

Slumping desiccant in a side channel

The desiccant material is slumping in the side channels and flowing out into the bottom channels.  Rusting of the channels is also common as can be seen in this window from the same house. 

Rusting space of a failed seal

Rusting space of a failed seal

Windows that are not in the direct sun are much less affected, with windows on the West side being the next most common.

So are these windows with the Warm Edge technology spacers failing prematurely?  Only time will tell for sure—but I am beginning to think so.

Perhaps we need to re-think the whole business of double pane windows for our homes.  A return to the removal pane type double pane windows like Pella (still makes) and Anderson used to make could be an option and makes a lot of sense on many levels.

By Charles Buell, Real Estate Inspections in Seattle

If you enjoyed this post, and would like to get notices of new posts to my blog, please subscribe via email in the little box to the right. I promise NO spamming of your email :-D


How to donate if you appreciate the information provided

I often get requests for information and help with specific reader questions.  I enjoy doing what I can to offer my opinion or help.  If you find the information was useful and care to send a monetary donation of appreciation, I would really appreciate it.  I will leave the amount up to you, and of course not donating will always be OK.

Thanks, Charlie

Select Payment Method
Personal Info

Donation Total: $0


  1. Bob Sisson says

    Nice article. I have started seeing these in limited quantaties. I also see them on NEW home at the final occasionally, and have a hard time getting the builder to replace them becasue they haven’t broken or fogged yet, just look ugly. Now I have some more info…Thanks.

  2. Hi Charlie, do you have a photo or link to the windows you mention in the last paragraph, I’m curious. 🙂 thanks Jana

  3. Do you think that Vynil Spacers are any better?

    • Charles Buell says

      George, I watched your video and found it interesting. I have never seen a sash where the glass is integral with the sash. Everything around here, the glass is a component that is inserted in the sash–not built into it. Would be interested in knowing what failure rate your windows experience. My only thought would be how glass would get replaced on fixed sash in the field.

  4. Windough Watch says

    “part of the reason why replacing windows will never pay for themselves in terms of energy savings. ”
    Clark Howard has been saying this forever on his show. But what about areas like in the Dakotas where winters are extreme lows often long periods of -20s-40s broken up with pole level blizzards?
    With rising gas and electric prices, and a 75-100+ year old home, which is NOT uncommon here, how could replacement windows not pay for themselves in a few years?

    • Charles Buell says

      The older and more drafty and uninsulated a home is the quicker the payback for windows will be. However once the home has been insulated and air sealed the payback goes away. That said, in the Dakotas you would likely want to replace them for other good reasons, such as air infiltration, and moisture control. It can be very difficult to maintain high enough moisture levels in homes with leaking windows that are drawing in very dry air. It will remain true that the seals will fail before they pay for themselves in energy savings if the home is insulated and air sealed. If you have a limited budget, in terms of saving energy, it is generally going to make more sense to throw those limited dollars at insulation and air sealing than it is to new windows.

  5. I have a window with a metal spacer manufactured by Ply-Gem that failed catastrophically within a year of installation. The window has water pooled between the panes. Ply-Gem refuses to do anything about it. I’m very frustrated with double paned windows because it looks like all manufacturers have these sorts of complaints. I think they’re refusing to honor warranties because the failure rate is so high!

  6. Jennifer Foley says

    Hi Mr. Buell,
    I have window problems in my new home!
    I bought a 2017 Giles Manufactured home last fall and moved in November 4, 2017. I live in Kentucky, and it was already cold weather. It didn’t take me long to realize the new home had drafty windows!!! (Vinyl windows Series 700/E700) I could feel cold air POURING IN from the channel marked in photo #1. That air seemed to be entering thru a hole at the bottom of the frame, photo# 2, and that hole connects with the slot on the outside of the frame, photo #3. It’s just an open channel from the outside!
    My question is, isn’t there supposed to be some sort of insulation/obstruction to prevent air from freely flowing in on these windows? If I haven’t sent enough information in these 3 photos please let me know what you need to see and I’ll send more photos. What can I do to correct this problem?

    • Charles Buell says

      There should be no direct connection between that slot and the interior. If there is there is weather-stripping missing likely or something else I am not seeing.

Speak Your Mind

* logo

This site uses Akismet to reduce spam. Learn how your comment data is processed.