Window Distortion Question

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Window Distortion Question

#1 Post by BoogieWoogie » Mon Jul 31, 2017 4:51 pm

I'm looking at replacing (myself) our original aluminum windows with vinyl before we paint the house. I would like to go with new construction windows so I can get down to the bones of the house and make sure things are sealed properly. We had a few leaks this last winter so I want to make sure there is no damage and that everything is proper.

As I drive around the neighborhoods, I see a wide variety of windows that have been changed out. The ones that stand out are the ones with glass that does not appear to be flat. I know with the low-e coatings and glass thickness, you can get double images in the reflections which is not a big deal but this is a different issue. It ranges from bowed centers (either convex or concave) to buckled edges where the window looks mostly flat but the bottom suddenly transitions and distorts the reflection.

I went to a new construction area that was installing Cascade windows and looked at some of the homes. Some looked really good and others showed visibly distorted reflections. I took a 24" steel rule to identical windows that were side by side and one was bowed in.

The window people I have talked to have been unable to explain what is going on with the windows. Some try to explain it away as the reflections of the multiple layers of glass but I know the cause is distorted glass. Could it be caused by the pressure differential (or temperature) between where the glass assembly occurred and where the home is? Say it was argon filled in a high elevation plant (or a really hot day) and then was shipped and installed somewhere closer to sea level or a cooler climate. Would that cause the two pieces of glass to suck in or push out and distort the glass? Maybe it's due to glass thickness and a thicker glass would hold flatness better against the forces of a vinyl frame shifting with the house and flexing the assembly? Maybe it's just poor installation in an opening that is not planer? Could it just be that all glass varies like this and the coating makes it highly visible?

I've looked at a couple of Jeld Wen installations and windows in Home Depot that look flat and clean. I really like the feel of the Anderson frames that are vinyl mixed with wood from their factory. Their frames feel much sturdier than the typical vinyl window frames and don't flex with as easily. I'm hesitant to buy windows from a major retailer like Home Depot as my perception of the quality they carry isn't stellar.

For the money I'm about to shell out for new windows, I don't want the front of my house to look like a series of fun-house mirrors. What's going on here so I can make sure to get a aesthetically pleasing result and what brand would you recommend that wouldn't break the bank. It's a mid-grade tract home and we're planning on being there for 10+ years.

The house is located in northern California about an hour north of San Francisco.

Thank you for your expertise!

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Windows on Washington
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Re: Window Distortion Question

#2 Post by Windows on Washington » Tue Aug 01, 2017 6:49 am

Without knowing which windows you were looking at, it is impossible to say.

Low-e is reflective and will generate that reflection that is part of what you are seeing. That said, the glass should be flat.

Anything that might be the result of an over-pressurized IGU is going to fail pretty soon thereafter so I do not suspect it is that.

If you like the Andersen product, they are a solid company and make a good window. You wouldn't be making a bad decision going with them.

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Re: Window Distortion Question

#3 Post by TheWindowNerd » Tue Aug 01, 2017 8:22 am

If you go with AW I would only sugest the following series 400 Wood wright, A series, E series.
If you need something from them less expensive look at the 200 TW.

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Re: Window Distortion Question

#4 Post by tru_blue » Thu Aug 24, 2017 11:41 am

Three possibilities come to mind as to the distortion you've seen in windows. WoW mentioned one of them - Low-E coatings on the glass are reflective and that can account for some of the distortion you see. There are several types of Low-E coatings available, with one, two, or three layers all pretty common. What's more some have purple-ish, pink, or even green swirls/hues, but those wild colors are primarily seen on units from the 1980s & 1990s.

Another "cause" for distortion is tempered glass. Tempered safety glass is required by code for certain applications, such as in all doors or above tubs. It's also common to find tempered glass in windows that are around 6 feet tall or taller. While tempered glass is much stronger than non-tempered ("annealed") glass, it is slightly wavy and distorted compared to annealed glass.

The third issue that comes to mind is regarding argon gas. The organic seal that seals two or more pieces of insulating glass together is good at sealing air between he glass, but the argon gas filling can and does actually leak outward at a slow rate over the years. The rate of leakage has been widely reported, typically between less than 1% to as much as 8% per year (usually the amount is reportedly on the <1% end, depending on the manufacturer). When argon leaks out by working its way throughout the sealant's molecules (without breaking the seal of the insulating glass unit), air does not leak in to take its place. This can cause a vacuum to start forming between-glass, with the glass panes bending inward to the point where they can almost touch one another. On bigger units (especially tall casements or doors) it is more noticeable, and can give the appearance that you described as "fun-house mirrors."

Another reason to go with a manufacturer that has a good track record with glass longevity.


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