New Product Focus
Webinar Teaches Architects
Benefits of High-Performance Fenestration
A number of architects tuned in April 16 for a webinar that offered
insight into the role of glass and fenestration systems in creating energy-efficient
buildings. The webinar, titled “Energy-Saving Architectural Solutions
for High-Performance Buildings,” was sponsored by Lawrence Berkeley National
Laboratory (LBNL) and Alcoa.
Moderator Jackie O’Brien of Alcoa opened the session
by commenting, “As many of you know, more than one-third of the energy
consumed in the U.S. is consumed by commercial buildings.” And, O’Brien
asserted, it’s a figure that will need to change. She pointed out that
$50 billion in line items in the recent stimulus package referenced building
construction or renovation, making knowledge of energy-efficient systems
more important than ever.
Steve Selkowitz, program head of the Building Technologies Department
of LBNL, also addressed the “big picture” view of energy use in the United
“Over $400 billion each year is spent on energy to cool, heat and light
buildings,” he commented.
Selkowitz told his audience that there are three paths available when
it comes to specifying the windows. The fist option is to “just meet the
code” with small windows that offer nothing “special” in terms of shading
or daylighting. “If you’ve just met the building [code] you’ve designed
the worst building you’re legally allowed to,” he cautioned listeners.
The second option is to use conventional “good solutions,” such as modest-sized
windows and skylights. Many of these options now utilize low-E coatings
and double-glazing, as well as options such as manual interior shading,
to maintain a comfortable interior environment.
The third, ideal, option is the new opportunity for “transparent intelligent
façades.” Selkowitz explained that upon adding more glazing, a
better set of tools is needed for optimization of the system, including
automated shading and dimmable lights.
He also pointed to two challenges. The first is finding ways simply to
become energy-efficient by minimizing winter heat loss and summer heat
gains. The next step, which is growing imminently more probable, is utilizing
the window in the creation of a zero-energy unit. These systems likely
will need operable façade components and should rely on automation
to best cooperate with HVAC systems and other utilities. Specifically,
lowering lighting costs by utilizing daylight is the biggest opportunity
for advancing the use of glass in energy-efficient buildings, Selkowitz
“This is the reason we often have windows in building. This is a great
opportunity but a great challenge,” he added. “The façade system
needs to be designed as part of an integrated system.”
During the second half of the webinar, Eddie Bugg, director of sustainable
solutions of Alcoa’s Kawneer Co., focused on practical applications for
achieving efficient buildings such as those described by Selkowtiz. But
before running through some of the company’s available products, Bugg
talked about the evolution of the LEED rating system from its previous
inception as version 2.2 to the 2009 version.
“Most noteworthy today is the doubling of points and credits for the energy
and atmosphere category,” he said, noting that credits for optimizing
energy performance have increased from 10 to 19, and that there are a
number of ways in which glass products can help achieve those credits.
Another change he pointed to is that the reference standard in LEED has
been updated from ASHRAE 90.1 2004 to 2007, “which also raises the bar
on being able to design buildings to energy code thresholds.”
In addition, credits for onsite renewable energy has increased from three
When it comes to choosing products to meet LEED credits and otherwise
improve building efficiency, Bugg noted, “You can’t come up with just
one [window] product to use universally on any project on your drawing
But as this program stressed, windows shouldn’t be overlooked in the critical
role they play in making buildings more efficient. AG
New Green Building Standard Could Help
Encourage Low-E Glass in Residential Structures
The development of the 2008 National Green Building Standard (ICC-700)
may help further promote the use of low-E glass. The International Code
Council (ICC) says its standard is designed to provide guidance for safe
and sustainable building practices in high-rise residential buildings
as well as new and renovated single-family homes.
The standard’s rating system allows architects/designers, builders and
communities to choose the levels of high-performance green buildings that
best suit their needs. For example, one key provision of the standard
is to offer energy performance starting at 15 percent above the baseline
requirements of the 2006 International Energy Conservation Code (IECC).
“Whether they use the performance option or the prescriptive path, the
standard will reward lower solar heat gain coefficients (SHGC) in the
south, and lower U-values in the north,” says industry consultant Thomas
D. Culp, Ph.D. “Both will promote low-E in all regions, and possibly some
triple-glazing in the north. Credits are also available for sun-tempered
design, passive cooling design and passive solar heating design. These
options reward builders for good practices such as optimally orienting
the building and glazing, using higher SHGC in the south, using larger
overhangs or other methods of shading, placing operable windows for cross
ventilation and using thermal mass. These can give three to 13 additional
points in the energy efficiency category, on top of points related to
the basic window and building energy performance.” www.iccsafe.org
Architects' Guide to Glass & Metal
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