How long will it take for triple-paned units to account for 25 percent of the U.S. window market?

John G. Swanson
June 11, 2008

The Talk, Page 2...

Survey Results for 06/11/2008:

How long will it take for triple-paned units to account for 25 percent of the U.S. window market?






Five to 10 years





10 to 15 years





Five years or less





More than 20 years





15 to 20 years





Questions and concerns about a possible shift to triple-glazing have been floating around ever since the Department of Energy issued its preliminary announcement about potential changes to the Energy Star Windows program. The new, more stringent U-factors they said they were considering for Northern climates in a couple years would be tough to meet with even the best double-glazed, gas-filled low-E coated glass package. To meet the new numbers, companies would have to go to triple-glazing, or perhaps some new technology.

Last week, I noted a statement made by DOE’s Marc LaFrance at the recent AAMA meeting. Pointing to climate change concerns and our country’s growing need for energy independence, as well as the resulting building code changes and evolution of Energy Star, he predicted, “All these things are moving forward together to move the industry from a double-paned package to pretty much a triple-paned package.”

So I thought I’d take a step beyond such a general prediction and see if the industry thought we’d be going from double- to triple-glass anytime soon. Apparently, a good number of people out there think it will happen. In total, close to 40 percent see it happening within the next 10 years. That’s not a very long time in our industry. Vinyl, and I would say low-E, were probably around longer than 10 years before they hit that 25 percent market share I asked about.

Another quarter of our respondents expect the shift will happen, but suggested it would take longer. It’s interesting to note, however, that one quarter don’t think it will ever happen. Never is a long time. I suspect those responses are somewhat colored by the very legitimate cost versus value question that triple-lite presents the industry—and our customers—now.

Going to triple-lite construction, most of us know, can add significantly to the cost of a product. It not only adds to the cost of the glass package itself, but the added weight might require a complete product re-design. Many manufacturers don’t see much of a payback in it—in terms of energy savings—for their customers either.

DOE, by the way, sees new technologies as one way to make the payback equation work better. For one, it is supporting efforts to develop new triple-lite options—replacing the center piece of glass with some type of lightweight plastic. This would be similar to the Heat Mirror approach of making insulating glass, but would utilize some solid material in place of a film. Vacuum glazing is another alternative DOE cites.

Both these ideas are great, but the industry is skeptical they will be ready—particularly within the timeline proposed for more stringent Energy Star requirements. And even if these concepts evolve and become products that can be manufactured and shown to outperform current products, there’s another hitch. Will they come to market ready to go with a 20-plus year life expectancy?

Paul Gary, a Portland, Ore., based attorney that represents window and door manufacturers, recently suggested the industry needs to lobby for some protection on this front. If cutting down on energy usage is a national priority—whether it’s because of climate change concerns or because we want to be more energy-independent—window and door manufacturers working to meet that goal should get some type of indemnification from legal action down the road.

He plans to state the case in an upcoming column of the magazine, but let’s look at a scenario: A new technology is developed. Window and door manufacturers adopt it to meet new codes and/or Energy Star criteria. Companies make real products in real plants, test them in a way that simulates 20 years of use and everything seems great. Then 10 years from now, we start seeing a deterioration in U-factors. Instead of the .20 originally simulated and tested, the number has creeped up to a .26. Next thing you know, some law firm starts signing up homeowners for a class action suit...and so on and so on.

Okay, I may have gotten off track on the triple glazing discussion, but based on some of the pained and puzzled expressions I’ve seen among window manufacturers over the past six months, I thought this was an idea worth floating sooner rather than later.

E-mail John Swanson at

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