One Lite at a Time
Glass Retrofit Options Begin to See Increasing
by Megan Headley
The Numbers: Empire State Building Window
• On-site processing of the Empire State Building’s 6,514 windows provided
cost savings of more than $15 million over the purchase and installation
of similarly efficient new windows.
• Through reductions in use of air conditioning and heating, the windows
should provide CO2 emissions savings of 105,000 metric tons in the next
• Installation and manufacturing savings: $14.95 million
• Estimated annual energy savings: $410,000 Source: Natural Resource
Of commercial buildings in the U.S. still had single-pane glass in 2011.
Deep retrofits can make good business sense for building
owners wanting to reduce the cost of utilities dramatically. And, while
the upfront cost of reglazing can be a deterrent, some experts say it’s
a lack of education that is keeping more building owners from requesting
your glazing services.
Others say it’s the fact that there are newer, cheaper and less disruptive
options available competing for this business.
Interest Is Out There
Overall, retrofits are on the uptick.
“We are definitely seeing an uptick in inquiries regarding façade renovation,”
says Mic Patterson, vice president of strategic development with the Enclos
Advanced Technology Studio in Los Angeles. “The early generation curtainwalls
are now approaching 50 years old and older, and they were not particularly
high performers to begin with.”
“We are actually seeing a lot more people doing these,” agrees Victor
Olgyay, a principal with Rocky Mountain Institute in Colorado. “In the
last six years or so we really started to double-down on existing buildings
and trying to demonstrate the amount of energy savings that is available
in existing buildings.”
Steve Champlin, president of Therm-o-lite Inc. in South Bend, Ind., has
seen his supplemental interior window system earn increased interest in
the last year. “This winter really woke people up,” he says.
January 2014 saw historic freezes in many parts of the country. Champlin
recalled one Chicago building manager in particular who had been saying
no to a window upgrade for years suddenly asking to install samples. “It’s
an older building, built in the 1960s, with single pane glass and a lot
of air infiltration at the openings. His systems were running 24 hours
a day every day during the winter, and they really couldn’t keep up so
a lot of pipes froze. This was the first time he had seen anything like
this and he had been there for 26 years in Chicago,” Champlin says.
On the other hand, building owners who are already in touch with the sustainability
movement see window upgrades as a next logical step. As Champlin points
out, “A lot of building owners have already gone after the low- hanging
fruit and now they’re looking at the more significant, substantial projects.
Window retrofits are very effective and very cost-effective.”
It’s difficult to argue with the numbers when comparing the utility savings
seen with today’s windows versus those of 20 or more years ago “When owners
and tenants replace older, less energy-efficient window systems with today’s
energy-efficient windows, building and unit values increase significantly
and monthly energy bills go way down,” agrees Bill Jones, Eastern regional
sales manager for EFCO Corp. in Monett, Mo.
By way of example, Jones cites a recent coastal condominium retrofit where
his company supplied all of the doors and windows. “The homeowner’s association
president told us their tenants’ monthly energy bills went down significantly
and the average unit value increased by more than $10,000 each within
90 days of completion. Regardless of building or project type, energy
efficiency, cost savings and increased property value are a real impetus
Patterson, however, says that few building owners pursue the performance
benefits of these windows. “What has driven the majority of façade retrofits
to date is aesthetics, not performance; performance has yet to emerge
as a prominent driver,” he says. “Building owners are interested in modernizing
building appearance, often as part of a renovation program with the intent
of bumping the building from a Class B or C to a Class A, with the goal
of higher lease and occupancy rates. So they do a little research and
consider the scope and cost of a façade retrofit, and often decide to
exclude the façade from the renovation program, instead pursuing the low-hanging
fruit, like new HVAC and mechanical systems, lighting and control systems.”
As the corporate push for sustainable buildings continues, and energy-efficient
solutions become more affordable, building owners are increasingly looking
to reach out to new solutions. Those made aware of the benefits to upgrading
glass will have two options for pursuing these savings: a deep retrofit
or secondary glazing.
A new guide on the topic from the American Institute of Architects and
Rocky Mountain Institute (RMI), Deep Energy Retrofits: An Emerging Opportunity,
explains that “planned roof, window and other major envelope replacements
provide opportunities for significant improvements in daylighting and
efficiency at minor incremental costs, providing the leverage for a deep
retrofit that reduces loads and potentially the cost of replacing major
equipment such as HVAC and lighting.”
“Deep energy retrofitting of the existing building stock, including the
façade systems, is the most effective strategy to transform the problematic
energy and carbon performance of the commercial building sector,” Patterson
says. He adds, “There are significant barriers to the adoption of this
strategy, however, including cost, disruption, risk and the split incentive
conflict resulting from the owner paying renovation costs but the reduced
energy savings going to the tenants. A strategy of appropriate incentives
to motivate building owners to undertake deep energy retrofits combined
with the implementation of more aggressive building code requirements
could significantly accelerate the conversion of existing buildings.”
In many cases, building owners see the most benefit of a full glass retrofit
when they are already seeking to replace their HVAC system.
That was the case with the well-publicized 2009 retrofit of the Empire
State Building’s windows.
“It’s a lot about timing, especially when we’re making those large capital
incentives,” Olgyay agrees. “One reason the Empire State Building worked
out so well from a financial perspective is that if you took the windows
as a separate item from the building, they had an [approximately] 17-year
payback. Because it was being done in conjunction with various other improvements
to the building … we reduced the cooling loads enough to then downsize
the investment in the central cooling equipment. We avoided $17 million
or so in capital cooling costs and that essentially paid for the windows.”
Champlin has seen this scenario play out time and again. “On buildings
that are 30 or more years old, it might be time for a heating or air conditioning
upgrade. For large facilities, many times [widow upgrades] are used to
reduce the total demand on the building. So if there’s a 2,000 ton chiller
[used now], they may instead put in a 1,500 ton chiller and the savings
between the two would more than pay for a window retrofit,” Champlin says.
While this holistic approach to building retrofits can save money for
building owners in the long run, it’s a new way for glazing contractors
to make money since these building overhauls are likely to use premium
Olgyay says that timing is the key incentive for these full glass retrofits.
“Time it right so [the owner is] not just paying for reglazing your whole
building but also doing blast mitigation or other things that have to
be done. If the building has to be resealed for some other reason or the
curtainwall is at the end of life, then it makes a lot more sense to get
the deep energy retrofit benefits,” he says.
Of course, few glazing contractors are likely privy to information about
when owners of older buildings are ready to upgrade their HVAC. However
it is the job of building energy modeling firms to know exactly this and
glazing contractors looking to specialize in retrofits can become valuable
resources for these firms.
“We work with several,” Champlin says.
Building modeling pinpoints where a building is losing the most energy
and where upgrades can be most beneficial. According to Champlin, prices
for these services are going down as more companies are offering these
simulations, and more building owners are making use of them.
“You can easily swap in different window types,” Champlin explains. Building
owners can see their existing windows as a baseline then calculate the
cost savings of new windows provided by your company to demonstrate how
they can change energy consumption.
“A lot of building owners have already
gone after the low-hanging fruit and now they’re looking at the more
significant, substantial projects.”
—Steve Champlin, Therm-o-Lite
Other solutions have emerged for when the disruption of removal isn’t
an option or when existing anchors can’t support the load of today’s new
products. Secondary glazing is becoming an increasingly popular way to
upgrade windows and curtainwall alike.
“Other options, beside replacement, involve some form of over-clad strategy:
adding a new skin atop the old one,” Patterson says. “This can provide
an excellent solution depending upon a number of often complex and interrelated
variables, and holds the potential to reuse at least some of the existing
materials. One form of over-clad is to add an outboard skin, actually
creating a double-skin system with a cavity between the two skins that
can act as an environmental buffer to the interior, or even be integrated
into the building HVAC system.”
When it comes to windows, rather than curtainwall, another picture emerges.
Champlin is the first to admit that when he came into the business of
secondary glazing, “I was very skeptical of what I heard … I thought,
‘[Energy savings] from a storm window?’”
“Usually you’re installing a window on the interior of the existing window,”
explains Vincent Grieco, New York regional sales manager for Crystal Window
& Door Systems in Flushing, N.Y. “That [new] window can be single- or
double-glazed and it offers thermal efficiency as well as noise, dust
or soot control.” Crystal has supplied its products for this application
in historic buildings. “They’ll use an actual vinyl window and because
the building is historic you have to line up the window with the existing
profiles to match the frame,” Grieco says.
“For buildings where [the owners] like the exterior design or for historic
buildings where they really can’t change the look of the building or if
it’s a high-rise where they don’t want to mess with taking glass out and
maybe having it pop out—there’s a lot of reasons why interior windows
work. We can build a frame on the inside and put a window system on the
inside to make it look new from the inside,” Champlin says.
Grieco says historic buildings are the biggest market for this technology.
“A lot of these historic or pre-war buildings are built with solid walls
where you have 18-inch-deep jambs. You can put in a full 3 ¼-inch window
and sit it on the interior without touching the exterior window. It’s
quick, you don’t need an engineer, all you need to do is match up the
sight lines. It’s pretty straightforward,” he says.
In many cases, this might be the simplest sell for a window upgrade, but
not necessarily one the window replacement company is eager to promote.
“I think the glazing industry is geared against interior retrofits,” Champlin
And why not? After all, Champlin promotes the ease of his product to building
owners as something that they can install themselves to significantly
improve a window U-value for the fraction of a full replacement. But it’s
an option that is gaining some traction and that glazing contractors will
need to become familiar with as a competitive product.
Champlin explains the product’s benefits: “In an existing building, we
won’t disrupt tenants, they don’t have to move. We can be in and out in
under an hour, where in other cases you might have to relocate the person
from the office and they rip out the whole window and you have to do it
during certain times of the year.”
Both approaches have merit. Unfortunately, both also have drawbacks.
And as Patterson points out, the sustainability of going in and retrofitting
dated curtainwall at the end of a set life cycle is a questionable practice.
“Can we really afford to replace the façade systems of our urban high-rise
buildings every 40 or 50 years?” he asks. “There are few options at this
point; the die was cast when the façade systems were designed. But it’s
worthwhile to consider how the façade systems we are designing and constructing
today will adapt to the conditions of an increasingly uncertain future.”
In general, few curtainwall contractors are considering the building skin’s
full life cycle
“Façade design practices typically do not anticipate and accommodate the
need for a future retrofit,” Patterson suggests. “As a result, completely
removing the entire façade system and replacing it with a new one is often
the only viable option. This same problem holds with our current façade
design practices as well. It is very possible that we continue to build
problems for future generations of building owners and façade contractors.”
More manufacturers agree new products, from anchors to frame, are being
adapted for simpler retrofits. But those solutions are still generally
few and far between. Explaining the full benefits of a glass upgrade,
including the ease of use for future retrofits, could be a way to help
ensure glass gets on the drawing board as a means for significantly improving
a building owner’s bottom line.
“I think the glass industry has been underselling itself,” Olgyay says.
“There’s been a huge focus on the aesthetics of glass, but glass is a
critical element in the building envelope and to show that it has multiple
benefits is really something that hasn’t been advertised by the industry.”
Glass companies and glazing contractors need to continue to sell the full
story, encouraging architects to look beyond the product as a simple piece
to be installed in a larger puzzle.
“For example, you’ve heard the stories in hospitals about people healing
more quickly when they have a view out their window,” Olgyay says. “Well,
that’s a great benefit to the insurance industry and the insurance industry
should be encouraging that. Similarly, the window industry should be espousing
those non-energy cost benefits of windows: comfort, satisfaction, employee
turnover, all of those things that then allow them to get to this higher
performance. It’s a little bit of a harder story to tell.”
But this multi-angled approach should prove valuable to companies seeking
to expand their market share by offering retrofit services.
Jones points out that these energy efficiency upgrades “translate into
cost savings, increased property values and satisfied owners and tenants.”
That’s the message to be spread, and there are plenty of places to spread
“According to the Department of Energy’s Building Performance Database,
in 2011 53 percent of the commercial buildings in the United States still
had single-pane glass,” Champlin says. “That’s where the market is.”
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