August 2016 — Retail Properties Quarterly —
Page 23
A
s an operator of retail prop-
erties, you’re always looking
to cut costs and save money.
When it comes to your ener-
gy bill, it is no kept secret
that your roof is an important player
in keeping your utility costs low and
saving you energy. Within the past
15 years, reflective or “cool” roofs
have been widely accepted as an
effective, low-cost solution to energy
loss and high utility bills, all while
reducing the carbon footprint of the
building.
This trend has been so prominent-
ly accepted that large cities such
as New York and Chicago have had
the use of these products mandated
for commercial roofing. And while
cool roofs have proven themselves
to work, there is a discrepancy often
overlooked in their fervent promo-
tion – location.
Reflective roofs often are pro-
moted with the general thumbs-up
of approval, meaning its use has
been interpreted to be equally effec-
tive and positive, regardless of loca-
tion, climate and weather. However,
research has shown that for north-
ern climates, where heating often
outstretches cooling costs, reflective
roofs carry high heating penalties.
White reflective roofs, when
installed properly, can reduce cool-
ing costs by reflecting ultraviolet
rays off the roof, allowing the insu-
lation to easily keep the buildings
inside conditions, thus reducing
the cooling costs. This same mate-
rial – often made from white ther-
moplastic olefin or TPO – does the
same reflecting process during the
winter season, making it harder for
the insulation to
maintain heat in
the building.
During the sum-
mer and in south-
ern climates, where
the weather is
generally warm,
this type of roof-
ing system makes
financial sense. For
northern climates,
where a major-
ity of businesses
spend more on heating their build-
ing than cooling it, a reflective roof
can be unfavorable, costing a busi-
ness owner a bigger carbon footprint
and hundreds in heating and wasted
energy. As charted by Engineering
Green Buildings in the February 2015
HPAC Engineering newsletter, most
of the cities in colder climates were
shown to have a significantly nega-
tive cost impact when using white-
reflective roofing.
Let’s use a hypothetical 1-story,
10,000-square-foot retail building
and compare the cooling benefit and
the heating penalty of using a reflec-
tive roof in various colder climates.
Denver, while having a cooling ben-
efit of $168, ultimately suffers a $435
heating penalty with white roofing.
Colorado Springs doesn’t do much
better with a mere $124 cooling ben-
efit, followed by a whopping $508
heating penalty. Other cities that
take major losses include Portland,
Washington, D.C., and San Francisco,
whose penalty reaches past $700.
Beyond costs and carbon emis-
sions, reflective roofing in northern
climates can cause condensation
when not implemented properly.
Because reflective roofing keeps
the roof cooler, during the winter
months, as the heat from inside the
building rises, condensation begins
to form underneath the roof mem-
brane. While condensation may not
cause a problem overnight, if not
solved, it could cause mold, spores,
rotting and eventual permanent
roof damage. This problem, how-
ever, is easily avoidable with the
implementation of a continuous
air/vapor retarder or several layers
of insulation. Condensation when
present in single-layers of insula-
tion can freeze and expand to tear
the edges of the insulation apart.
Take into consideration the R-value,
defined as the “unit of thermal
resistance for a particular mate-
rial,” or simply the “thickness” of a
material. The R-value is measured
by “a solid materials resistance to
conductive thermal transfer.” This
means the thicker the material (the
higher the R-value), the more resis-
tant it is to thermal transfer. With
the presence of several layers of
insulation, moist air has a more dif-
ficult time reaching the underside
of the roof’s membrane and causing
condensation.
Needless to say, when it comes
to your roof, the type of material
you use is important. Roofing is
no one-size-fits-all rule. Much like
real estate, it’s all about location. By
choosing a quality-roofing contrac-
tor, you will be provided a cost esti-
mate of the roofing materials best
suited to your climate. That being
said, regardless of the color, your
business should schedule a yearly
inspection to warrant the safety,
durability and quality of your roof.
s
Irene Sanders
Superior Roofing,
Aurora
Management
Colorado Springs doesn’t do much
better with a mere $124 cooling
benefit, followed by a whopping
$508 heating penalty.
