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Case Study #1 - Cool Metal Roof Saves Energy
Costs
 This case study involves a retrofit for
energy conservation using cool metal roof technology in
Paulding County, GA, USA.
In 2002-2003, the Paulding
County (Georgia) school district built two new elementary
schools: Bessie L. Bagget Elementary and Lillian C. Poole
Elementary. The schools were nearly identical: same size
(90,000 square feet), same HVAC (heating, ventilating and
air-conditioning) units, and the same orientation to the
sun. Both have metal building systems for the gym and
cafeteria. The remainder of each school uses conventional
structural steel with metal purlins and a metal roof.
It was proposed that the
schools be used to study the value of cool roof technology.
The goal was to see if one roof was truly more energy
efficient than another. Poole Elementary was constructed
with a metal roof that contained a full strength 70% Kynar
500-based (PVDF) coating that
used an infrared reflective pigment (reflectivity of 0.29).
Baggett Elementary was built with a metal roof that had a
non-cool Kynar (PVDF) coating (reflectivity of 0.12). The
roofs are both the same dark-green color. To preserve an
ideal comparison of energy consumption in the schools , the
two schools’ thermostats were set at the same temperature
and controlled at the administrative building.
Lillian C. Poole Elementary Powder Springs, GA
Cool Metal Roof, Solar Reflectance 0.29 |
Bessie L. Baggett Elementary Dallas,
GA
Conventional Metal Roof, Solar Reflectance 0.12 |
The two buildings opened in
November 2003. After the first full year of use, the cooling
and heating costs were evaluated, with electricity and gas
heating bills from the utilities. The reduction in cooling
costs from the cool Hunter Green roof far outweighed the
heating penalty from more gas heating that was required. The
overall cooling/heating savings on an annual basis exceeded
$8,000 based on the price of energy at that time with the
cool roof of identical color.
Never-before published
information from the utility company serving the school
district now reveals that after the fourth year of use, the
Poole School featuring the solar
reflective roof was saving approximately $15,000 in
electricity and gas costs, at the present price of
energy, compared to the Baggett school building. This
amazing difference verifies the claims of the energy cost
savings with cool metal roofing. Four years after the roof
was installed the savings are more than keeping pace with
the escalation of energy costs in that region.
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Baggett School Versus Poole
School, Energy Savings |
|
Greystone Power
(2006-2007) |
Baggett SR (12%)
Cost |
Poole SR (29%)
Cost |
Total/Annual
Savings |
|
Annual Electric |
$88,352 |
$78,045 |
$10,307 |
|
Annual Gas |
$24,989 |
$20,800 |
$4,189 |
|
Annual
Cost |
$113,341 |
$98,845 |
$14,496 |
Assuming that the projected
lifetime of the coating is 30 years (even though the
warranty maybe for 20 years against colour fading) , a total
savings of $450,000 is achievable, not including the likely
increase in fuel prices.
Over the past four years, the
cool metal roof has retained its color stability and
excellent solar reflectance property. The low coefficiency
of the PVDF coating allows the roof to shed dirt through
natural rainfall and preserve the performance
characteristics of the roof. This reinforces that cool metal
roof IS IN FACT a sustainable passive energy-efficient
product.
Today, after four years of
dedicated monitoring, the reflective cool metal roof is
proving the point. More importantly, the annual operational
cost reductions are substantial enough to provide tens of
thousands of dollars to the school district to purchase
needed equipment, programs and educational materials that
otherwise may not be available.
The savings represent real
money that the school district enjoys right now. The roof
continues to pay them back, and as the cool metal roof is
expected to perform for many years, the life-cycle cost of
the roof will remain very low while keeping the occupants
very comfortable. This is a true testimonial to the proven
tangible cost savings made possible with cool metal roofing. It is obvious, the
energy savings effects of
cool metal roofs would be more pronounced in countries with
warmer climates like Malaysia.
Do not wait any longer. For your next metal
roofing project, specify COLOURCOIL®
KOOL energy-efficient solar reflective pre-painted steel.
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Colourcoil
Product Specification Sheets - What's inside
Colourcoil product specification sheets
describe in detail the type of coating used as well as the
results of tests conducted in accordance with the relevant
ASTM standards. It is imperative that you compare test
results of other competitor's products with ours, so you get
the type of performance for what you paid for.
One important detail to look at is the
allowable colour change over a specified time. In the
example above, "A light silver colour, Metallic PVF2
Series, will not fade more than 6 units
delta E over a period of 20 years". This forms part
of our color fading warranty to our customers who use our
pre-painted steel for their metal roofs.
|
High
Performance pre-painted steel
(KOOL
energy - efficient, solar
reflective roofing metals) |
Warranty* against colour fading, chalking and
delamination |
Warranty* against corrosion |
Product Specification sheets |
|
 |
COLOURCOIL®
PVF2 SeriesTM |
20 yrs |
25 yrs |
click here |
|
 |
COLOURCOIL®
METALLIC PVF2 SeriesTM |
20
yrs |
25
yrs |
click here |
|
* Terms &
conditions apply |
For your next metal roofing project, ask your
metal roofing manufacturer what type of warranty is he
giving for colour fading. You should ask for, (1)
warranty period & (2) maximum colour change delta-E
values during
warranty period.
Click here to learn more about quantifiable warranty and
colour change.
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Why
is Metal Roofing considered “Green”?
 This
short article is featured here because one of our marketing
staff overheard a conversation of someone asking whether
asphaltic roof shingle maybe considered "green" or not.
The
largest use of petroleum asphalt is for making asphaltic
concrete for road construction and accounts for
approximately 80% of the petroleum asphalt consumed. Roofing
shingles account for most of the remaining 20% of asphalt
consumption. Every year over 13
billion pound of asphalt shingles go into land fills, which
could all be prevented because metal roofing is:
-
100%
Recyclable at the end of it’s lifespan
-
Metal
roofing has a lifespan 2-3 times as long as shingles
-
Metal
roofs already have recycled content of 20-30%
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Steel is
the most recycled material
-
Shingle Roofs are made up of more oil and raw
materials (see chart)
But what
about rainwater? Is there more pollution from a metal roof
or a shingle roof? The answer is shingle roofing is more
toxic because:
But what
about solar reflectance and insualtion? Which roof is more
energy efficient? Metal roofing is more energy efficient
because:
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Metal roofs are coated to reflect sunlight and have
infrared pigments to keep the roof cool in the
summer
-
Metal roofs are also much thinner and have less mass
which means they hold less heat given them a higher
emissivity
-
In some
countries such as U.S, metal roofs are tax credit
eligible for rebate!
And
finally, what about integrating solar? Metal roofs are the
best option for solar because:
-
You can
go with traditional solar panels using special
brackets which requires no roof penetrations or
-
You can
go with solar thin film, an aesthetically pleasing
and extremely durable option
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Need more
info?
Whether you are an
architect, engineer, developer, house owner or a metal
roofing or wall cladding manufacturer, our marketing team
will be most delighted to discuss with you on your specific
product requirements.
If you wish to make a factory visit, obtain a free brochure
or complete specifications and colour charts, please contact
our courteous and friendly marketing staff by calling the
nearest office or just drop us an email at
info@colourcoil.com.
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