Manufacturers Have Different Opinions on ENERGY STAR Draft Requirements
March 19, 2009
The debate over whether one type of glass is right for all regions
of the country has been going on for some time. Current ENERGY STAR
requirements specify that a window must have a certain U-value depending
upon the climate zone, but allow for any solar heat gain coefficient
(SHGC). However, last week the U.S. Department of Energy (DOE) released
its Energy Star for Windows, Doors and Skylights Revised Draft
Criteria and Report, which now specifies a SHGC for different
regions. Based upon the draft revisions, for example, the same windows
sold in the South-Central region will not be allowed in the North-Central
The ENERGY STAR draft requirements have a seen a mixed response
from glass manufacturers.
Paul Bush, manager of technical services for PPG, sees the changes
as a positive step.
"ENERGY STAR has always been a positive for the industry and
PPG has been involved from the beginning. We continue to support
the details of the revision and we think the use of multi-climate
zones has merit," says Bush "The more zones there are
provides the ability to maximize high-performance glazing products
by region, particularly in the Northern climate zones.
He continues, "[Studies] have shown the cost benefit of passive
solar in northern regions. [Prior to these draft requirements] there
was a one-size-fits-all approach, but now that's limited because
of the alternate compliance path. This way you'll have the best
product for the best region."
Some companies, however, may not view the draft as favorably. Cardinal
Corp., for example, supplies many residential window manufacturers
with high-performance low-E glass that has been used in areas all
over the country. In the July/August issue of DWM magazine (CLICK
HERE for that article) Jim Larsen, the company's director, technology
marketing, said he's certainly not against the requirement of solar
gain in the north and agrees that it can be beneficial. The issue,
he says, is knowing the trade-off.
"The trade-off is that you really need an active homeowner
to get the true benefit of the passive solar gain without the discomfort
penalty," said Larsen. "You have to practice opening and
closing the windows during the swing season, opening and closing
your blinds and certainly looking at having some building attributes
that are more advantageous toward using passive solar gain."
He added, "You must always go for comfort first. One of the
premises and the reason why high SHGC didn't stay a fixture in the
northern marketplace is because a typical house ended up sacrificing
(Editor's note: at press time Mr. Larsen had not responded to
USGNN.com's request for comment on the current ENERGY STAR draft
The DOE is taking comments on the revised criteria March 25. (CLICK
HERE for information on where to send comments.) The final criteria
will be published on March 31, 2009. The effective date for phase
1 criteria is January 1, 2010.
HERE to view the full draft criteria.
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