What do you think of most stringent U-factor number being considered for 2009 criteria?

John G. Swanson
January 23, 2008

The Talk, Page 2...

Survey Results for 01/23/2008:

What do you think of most stringent U-factor number being considered for 2009 criteria?

It should be less stringent.





It should be more stringent.





It's reasonable.





I can’t say I expected the industry would ask for more stringent requirements when the Energy Star program is revised, but I will admit to being a bit surprised at how overwhelming the results of last week’s poll were. With the Department of Energy sharing some of its ideas before issuing a final plan, we noted the potential for a U-factor requirement of .30 in the Northern climate zones when the new criteria go into effect sometime in 2009.

Our poll focused specifically on that number, and 85 percent of respondents said that .30 was too stringent. Adding to the weight of the response, I’d like to note that while our previous record for votes in one of our WDweekly polls was 700 responses, we received over 1,200 responses this time around.

Looking on the other side of the equation, about 5 percent of respondents this week said the .30 is reasonable, and about 10 percent suggest the new requirements could push the envelope further. One member of this minority, a reader who works for a commercial glazing company in Wisconsin, offered this opinion: “As much as I like to see projects with a ton of glass, the bottom line is windows are the weak link in the overall R value of any building. A U-factor of .3 equals an R value of 3.33. Walls are insulated to, what, well into the R-20's? I also just built a house, and I regret putting in so many windows. I see dollar signs flowing out the windows in the winter-time. I support lowering the U value as far as possible to motivate people to save energy and motivate companies to offer better technologies to make windows more efficient.”

No one would argue those aren’t laudable goals—and personally, I think the industry will deliver better numbers in the future, but there still are hurdles to overcome. I suspect that’s the feeling within the American Architectural Manufacturers Association, which, like most of our respondents, has reservations about making the requirements too stringent. AAMA is actually lobbying for a two-tier Energy Star system, but says if that’s not possible, it would look for a U-factor reduction on the order of 10 percent on the current criteria. “We cannot support unrealistic targets,” cautions John Lewis, AAMA technical director. “Dramatic reductions in U-factor would require the redesign and retooling of entire product lines for many manufacturers, and this is not possible in a matter of months.”

A 10 percent reduction from the current .35 U-factor in the North is closer to the .32 number at the high end of what DOE is considering. It will be interesting to see what the response to this week’s poll question—and whether much of the industry believes that is reasonable. My guess is that companies that can sell a double-glazed unit and still meet that number will say yes, but those that have to go to triple-glazing are likely to say no. Of course, the companies already offering triple-glazed high performance units are probably the ones arguing for the .30 now.

I don’t envy the DOE. They have a tough decision coming up. They have legitimate reasons to make their numbers tougher than code. After all, the goal of the Energy Star label is to identify a product offering superior energy efficiency. If the numbers on the label are the same as written into a state’s energy code—theoretically a minimum acceptable performance level—that clearly isn’t the case. Code officials in many states, however, are looking to tighten required performance levels themselves. That’s one of DOE’s reasons for putting off a decision on what the new numbers should be—and may be a good argument for AAMA’s idea of a tiered approach.

I don’t pretend to know what the best solution is for the short-term. There are good arguments to move slowly and good arguments to push harder when it comes to Energy Star. A critical point I take out of the whole debate, however, is that triple-glazing appears to be coming to a window near you if you’re in the North.

When DOE issues its new Energy Star criteria for 2009, it also plans to announce what the criteria will be 2012 and 2015, giving our industry some longer term targets. Even if we get a Northern zone U-factor that can be achieved with double-glazed windows in 2009, it seems almost inevitable that triple-glazing will be required to reach the number established for 2015, and maybe even the level set for 2012.

And companies selling in Northern markets may not have the option to say, “Let’s see if we can live without an Energy Star label and stick with double-glazed units.” Code officials won’t be far behind DOE in ratcheting down the numbers.

Perhaps I’m wrong. Triple-glazing may not be inevitable for Northern markets. I’ve heard a number of people argue it’s hard to cost-justify the shift from double to triple glazing. The increase in energy savings doesn’t pay for it over reasonable time frame. These people may be right and the next level in window and door performance may lead us beyond triple-glazing—or at least triple-glazing as we know it—to completely new technologies. Whether see more triple-glazed windows or not, I think, products for colder climates could see some profound changes in design and manufacturing in the not-too-distant future.


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I keep hearing about U factors of .32, .35, .20, .15 and how they will save me all this money.

What I would like to know, is my current windows have a .38 U factor, and my wife and I are considering replacing them with new windows.  If we were to go to a .32 U factor and all other factors staying the same.  What could I expect to save per year?  Most of my windows are 32 X 69. 

Is there enough saving to warrant the expense. 

Based on the Energy Star maps I live in the northern region.  We heat with natural gas, and use window air conditioners in the summer.  We have just had the rest of the house insulated with blown in insulation.


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