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conduction and convection.
The reflective surfaces inhibit radiation heat transfer.
If the bottle starts out hot, it stays hot because very
little heat is transferred to the cooler outside. If
it starts out cold, it stays cold because very little
heat is transferred from the warmer outside.
What if RB collects
dust over a period of time? Will it still work?
This very issue has been studied by research institutes.
Most attics don't accumulate enough dust to affect RB's
ability to save energy costs. Thousands of homes and
structures have had RB installed for as long as ten
years or more with no significant accumulation.
Wont my roof get hotter
when I have RB in my attic?
No. RB has been used extensively in the south, showing
no difference in roof temperatures, as confirmed by
field tests.
Do I have to take out
my old insulation to put RB in?
No. RB actually makes your present insulation more effective.
Where do you install
RB?
RB can be laid over your present insulation like a blanket
or stapled under your rafters or crawl space. Consult
your local RB dealer for your best application.
What about foil-faced
fiberglass? Isn't it just as good as RB?
No. The foil on the fiberglass is in direct contact
with the attic floor. Aluminum foil becomes more conductive
when in contact with a solid surface. The air space
facing the foil surface is of primary importance.
Why couldn't I just
put plain kitchen foil in my attic?
You could but kitchen foil would not be nearly as effective
as RB because it is only 22% aluminum, with other alloys
and minerals that will cause it to break down over time.
The RB is 99.5% pure aluminum, so is much more reflective
than foil and does not break down over time. Also the
RB contains small perforations so it breathes and doesn't
cause condensation.
I already have plenty
of insulation in my attic. Do i really need RB?
Regardless of how much insulation you have in your attic,
adding RB will save on your heating and cooling expense,
and keep you much more comfortable. Energy savings for
heating and cooling can vary from 10% to 25% depending
on a number of factors, including climate, building
configuration, materials used, site, family size and
lifestyle. Your RB dealer has been trained to evaluate
your home or business and advise you of your savings
potential.
Has RB been tested
by a qualified independent laboratory or government
agency?
The Florida Solar Energy Center at Cape Canaveral has
tested radiant barriers in both small scale laboratory
and full scale building models. Their results indicate
that radiation barriers provide significant resistance
to heat transfer. Current test conducted by the Tennessee
Valley Authority, and the University of Mississippi,
support the findings at the Florida Solar Energy Center.
Northeastern Illinois University conducted winter tests
in residential and commercial structures using infra-red
thermograph photography. The photos showed significant
resistance to heat transfer over the regular insulation.
Will dust collecting
on the top of the product hurt its effectiveness over
a period of time?
A1 "Aluminum foil exposed in a vertical position
since 1929 to the dust and fumes in the Heat Measurements
Laboratory, M.I.T. Samples of this foil have been removed
from time to time and the emissivity determined. Over
a period of 10 years no appreciable change in emissivity
was found." "American Society of Heating and
Air Conditioning Engineers' Journal Section," Jan.
1940, Professor Wilkes, M.I.T.
A2 "Thin layers of dust readily visible to the
eye do not cause very serious lowering in the reflective
power. The appearance of the surface is not a reliable
guide as to its reflectivity for radiant heat, and foil
which appears dark or discolored may have lost little
in insulating value if the surface film is thin."
-The National Bureau of Standards, U.S. Dept. of Commerce,
Letter Circular - 535.
Will the aluminum corrode
and lose its effectiveness?
A1
"Hundreds of samples of aluminum foil have been
stored in the laboratory for various periods of time
up to 10 years with no visible signs of deterioration."
"American Society of Heating & Air Conditioning
Engineers' Journal Section."
A2
"Aluminum is highly resistant to the effect of
corrosion . . . Aluminum is constantly being used where
it is exposed to weather, salt spray and other conditions,
which would adversely affect most metals." The
United States Rubber Co. Booklet, "Serving You
Through Science." Page 5.
Q. Do I need a radiant
barrier if my home is already well insulated?
A1 SUMMER:
"A radiant barrier system can stop 97 percent of
the thermal radiation across an attic space. If it is
not stopped, that radiant energy would be absorbed by
the ceiling insulation and eventually be transferred
to the living space below." "The Solar Collector,"
Quarterly Newsletter of the Florida Solar Energy Center.
"The heat storage capacity of reflective insulation
is low. As a result, it does not store heat during summer
days, only to pass it on down into the rooms of the
house from the attic at night when coolness is most
apt to be desired from the point of view of sleeping
comfort." "Progressive Architecture,"
Nov. 1949, Page 76.
A2 WINTER:
"CONCLUSIONS: Reflective foil retrofitted to fiberglass
insulated . . . buildings is demonstrably effective
in reducing heat loss . . . Installation of foil in
uninsulated buildings would show even more pronounced
reduction in heat loss." "Effects Of Reflective
Foil On Heat Loss in Attic Floors and Metal Building
Installations," Northeastern Illinois University,
Prof. Charles Shabica, May 20, 1986. |
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