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DETROIT --- A $120,000 window
film retrofit aimed at reducing energy costs and tenant complaints at
Edison Plaza office building here is expected to yield a payback in just
under three years.
Having applied reflective, low film to about 80,000 square feet of
glass in December, Edison Plaza property management expects to lower the
building's annual electricity costs by about 4 percent, or $32,700. That
reduction will come from a projected summer peak demand reduction of 93
kilowatts (kw) and an annual energy consumption reduction of 360,000
kilowatt hours (kwh), according to Jessica Toupin, a property manager
with Hallwood Management.
The retrofit earned $24,080 in
rebates from local utility Detroit Edison Co., lowering its payback to
2.9 years. The rebates were awarded under the utility's Custom Equipment
Incentive Program, according to Paul Cramer, program manager. The
demandside management program is open to the utility's industrial,
commercial, and institutional customers and pays $200 per kw removed
from summer peak and 1.5 cents per kwh conserved.
The glazing treatment selected
for the retrofit was Llumar Series E silver film by C P Films,
Martinsville, Va. The film has a shading coefficient of .24, reduces
solar gain by 79 percent, and cuts radiant heat loss by 69 percent,
according to William F. Kish, President & Owner of installing contractor
Solar Reflective Films, Farmington Hills, Mich. A scratch-resistant
coating for easy maintainance and 7 year manufacturers warranty are
standard with the E1220 film, he noted.
By using film to reduce solar
gain, building managers will be able to throttle back the building's two
820 chillers, saving on both energy consumption and demand, Toupin told
EUN. With almost an entire cooling season of bills in hand, she reported
the retrofit is meeting savings estimates.
Chiller load has dropped from
100 to roughly 80 percent, she continued.
"We used to have to turn on
our chillers at three or four in the morn to cool the building, and now
we can run them at 6:00 a.m. and they don't work as hard," Toupin added.
She said the project might
exceed projections through additional cooling season energy savings and
lower winter steam heating costs. However, as of EUN press time. Toupin
was still gathering utility bill data and couldn't quantify additional
savings, but she estimated that the retrofit would reduce annual energy
costs significantly.
The project's effect on tenant
comfort was immediate, Toupin noted, saying it has virtually eliminated
temperature complaints.
"It was a constant cycle of
heating the south side and freezing the north," she related. "In the
morning we had at least 10 calls from southside tenants complaining that
they were too hot and in the afternoon, there would be at least four
calls from north side saying they were too cold."
In April, when the chillers
are sometimes down for repairs, occupants would also frequently say they
were uncomfortable, Toupin continued.
The film has created a more
even distribution of air conditioning load, making the transition from
heating to cooling seasons more comfortable, she said. Toupin called
window film a "quick hit" measure, but told EUN that Detroit Edison
incentives were a critical factor in the decision to have the entire
building treated. Originally the end user was presented with two
prospective paybacks based on film application to either two or four
sides of the building. Applying film to only the west and south sides
would have earned a payback in 6.5 years and a rebate of about $6,500.
Hallwood opted to retrofit all four sides because of the more favorable
return.
While price and product
quality were important, the property manager also assigned a high value
to proper installation. Toupin told EUN she shopped around, asked for
references, and visited a number of buildings to gauge
prospective installers' craftsmanship.
After narrowing the field of
film distributors to two candidates, she had each distributor install
test panels on various parts of the 24 floor building. The panels made
a dramatic difference, she recalled.
"You could feel the difference
on your skin when you stepped in front of one of the test panels and
stepped back into an untreated area," Toupin notes.
In the end, the quality of two
candidate's workmanship was equal but the Llumar film cost about half as
much as the other product, she said.
While the building appearance
is expected to benefit from the retrofit, Toupin ranked enhancing
aesthetic appeal third in importance after energy savings and occupant
comfort. Because the mirrored film was applied over existing
bronze-tinted glazing, Toupin was concerned about mixing the two shades.
However, the blend resulted in a golden hue that sets the building apart
from others in the area, she observed.
Toupin told EUN that tenants
near southfacing windows used to draw their blinds frequently to cut
heat gain and ensure privacy. This strategy often created an unappealing
non-uniform appearance from the street, she said.
"Nobody wants the sun beating down on them in their offices, and even
with the brown tint, you could look right into the building. The blinds
just made the building look bad, and that's something that is important
to prospective new tenants and lease renewals," Toupin concluded. |
