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WHAT IS A RADIANT BARRIER?
Radiant barrier, when simply laid on top of existing ceiling insulation,
helps reduce heating and cooling bills, extend the life of heating and
cooling systems, and increase the comfort level of a home.
Radiant barrier consists of two sheets of industrial grade
aluminum adhered together and tri-laminated to a thermal break to create a
two-sided reflector. It cuts heating and cooling costs by lowering the
amount of heat transferred into a home in the summer and out of a home in
the winter.
The Radiant Barrier Reflective Insulation technology was developed by NASA
over 40 years ago to protect astronauts in the Apollo program from
temperatures that ranged from 250 degrees above zero to 460 degrees below
zero Fahrenheit. Radiant Barrier Reflective Insulation has been applied to
every spacecraft since then, including unmanned spacecraft with delicate
instruments that need protection from temperature extremes. The same
technology is also applied to astronaut's space suits, protecting them
during space walks.
Since the 1970's private industry has had the opportunity to apply Radiant
Barrier Reflective Insulation technology to various commercial
applications. This NASA technology has been applied to energy conservation
techniques for home and offices, and even specialty applications such as
candy wrapping, thermos bottles, coolers, windshield covers, automobiles,
fire suits, space blankets for forest rangers and fire departments, race
cars, air conditioning and heating units and ducts, boilers, water pipes,
poultry farms, survival blankets, and refrigeration trucks to name a few.
HOW DOES A RADIANT BARRIER REDUCE
ENERGY COSTS?
Heating and cooling costs are a very large portion of your energy bill.
The most effective way to cut these costs is to lower the amount of heat
transferred into your home in the summer and out of your home in the
winter. Heat is transferred in three ways: radiation, conduction, and
convection. All heat transfer begins with radiation. Infrared rays or heat
waves are radiated in a direct line from any heat source whether it be the
sun, a fire, or the electric element of a space heater. These heat waves
are either reflected or absorbed by any object that they come in contact
with. If they are absorbed, the process of conduction (heat passing
through solid materials) or convection (heat movement by air currents can
occur.) Your roof, insulation, walls and ceiling are all materials that
absorb and conduct these heat waves.
HOW DOES IT WORK?
Radiant barrier is made with two sheets of aluminum adhered together to
create a two-sided reflector. When installed directly on top of your
insulation, heat waves put off by your roof decking in the summer are
reflected by the radiant barrier before they have the opportunity of being
absorbed by your ceiling insulation, thus keeping your home cooler. In the
winter, the radiated heat waves from within your home are absorbed by your
ceiling and conducted up through your insulation into your attic. In this
case, the down-facing side of the radiant barrier reflects the radiant
heat waves emitted from your insulation back down toward your living area
instead of allowing them to simply escape into your attic. This process
eliminates heat loss through your ceiling, thus saving you dollars.
WHAT ABOUT INSULATION?
Insulation is designed to absorb heat passing through your ceiling.
Radiant Barrier reflects rather than absorbing heat. In fact, insulation
with no radiant barrier can be a detriment during the cooling season
because after absorbing heat during the day, it can continue to conduct
that heat into your home throughout the evening.
WHAT IS THE "R" VALUE OF RADIANT
BARRIER INSULATION?
The "R" value depends on the number and size of the airspaces surrounding
the Radiant Barrier Insulation and on the direction of the heat flow.
Since Radiant Barrier Insulation is usually installed on top of the
existing mass insulation, its R-value is a moot point. It is Radiant
Barrier Insulation's ability to reflect heat that makes it such an energy
saver.
DO I HAVE TO TAKE MY OLD
INSULATION OUT TO PUT RADIANT BARRIER INSULATION IN?
No. Radiant Barrier Insulation actually makes your present insulation more
effective.
WHERE DO YOU INSTALL RADIANT
BARRIER INSULATION?
Radiant Barrier Insulation can be laid over your present insulation like a
blanket or stapled under your rafters or crawl space.
I ALREADY HAVE PLENTY OF
INSULATION IN MY ATTIC. DO I REALLY NEED RADIANT BARRIER INSULATION?
The
Department of Energy's Radiant Barrier Fact Sheet
states that homeowners can expect up to 17% cooling savings depending on
climate, current amount of insulation in the attic, and household energy
use. Many of our customers claim to have seen higher results, but these
results have not been scientifically verified by a 3rd party.
HAS RADIANT BARRIER INSULATION
BEEN TESTED BY A QUALIFIED INDEPENDENT LABORATORY OR U.S. GOVERNMENT
AGENCY?
The Florida Solar Energy Center (FSEC) 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 tests conducted by the Tennessee
Valley Authority, Oak Ridge Laboratories in Tennessee, 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. View
the FSEC Radiant Barrier Report »
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