Inside Insulation:
Providing Superior Performance and Easy Installation
Matt Struss,
Posted
04/01/2008
Heat moves toward cold. This is the basic idea behind all
insulation products. By reducing the transfer or flow of heat,
corporate conglomerates and homeowners alike can reduce their
heating and cooling bills and increase the overall comfort of their
buildings.
There are three modes of heat transfer: convection, conduction and
radiation. Convection is the transfer of heat through moving air
currents such as wind. Conduction is heat flow through a solid
object such as a skillet on a stove. Radiation is the transfer of
heat energy through infrared light waves. The best example of this
is the sun. Light waves from the sun radiate to Earth and heat up
the surfaces with which they come in contact. You cannot see these
light waves, but when you step into the sunlight, you can feel them
warming your skin.
The best way to prevent the transfer of heat from convection is by
sealing all air infiltrations into the building. Testing completed
by the Florida Solar Energy Center, Cocoa, Fla., stated that for an
average 1,500-square-foot (139-m2) home in central Florida,
infiltrations made up 10 percent of the home's heat
gain/loss.
Typical mass insulations such as fiberglass or cellulose are used
to slow the rate of heat transfer through conduction. Heat moves
through these products at a slower rate than they would through
another material such as wood or metal. The value used to measure
the rate of heat transfer in these products is an R-value. The
higher the R-value, the greater the resistance to heat flow.
Understanding radiant heat and corresponding insulation is slightly
more technical. Radiation is a light wave and has no temperature.
When these light waves strike a surface of a material, they
transfer energy to the molecules of that material causing them to
move faster and heat up. The terms used to describe the transfer
and absorption of radiant heat are emissivity and reflectivity.
Emissivity refers to the ability of the material to allow radiant
heat to pass through. Reflectivity is the amount of radiant heat
reflected or not transferred from a material. Emissivity and
reflectivity are proportional. If a material has an emissivity of
0.85, then it has a reflectivity of 0.15. For example, wood has an
emissivity of 0.9 and a reflectivity of 0.1, meaning it absorbs and
transfers 90 percent of the radiant heat. Reflective insulation and
radiant barriers reflect at least 90 percent, or 0.9, of the
radiant heat and only allow 1 percent, or 0.1, of the radiation to
transfer.
When architects select building insulation for a project, they do
so based on the needs of their client (energy cost savings, comfort
or aesthetics). Then they evaluate the building insulation options
for the specifi c type of application-as in the case highlighted
below, a metal building with little or no insulation. In addition,
the architect may have an interest in seeking out products that
could qualify the client's building for green building
certification (LEED for Existing Buildings).
When selecting any type of insulation, the architect should always
thoroughly review technical data, samples, installation sheets and
product warranties. And they should work directly with the
manufacturer to obtain a list of qualified installers in the
location of the project.
Iron Works
Fitness, a 20,000-square-foot (1,858-m2) fitness club in Hueytown,
Ala., was looking to reduce air-conditioning costs and increase the
comfort level of their patrons during hot Southern summers. Radiant
heat emitted from the uninsulated metal roof down into the
building, conductive heat worked its way throughout the building
and convective heat infiltrated the building through small seams in
the building envelope. Iron Works needed an effective solution to
save money and minimize the fitness centers down time.
Iron Works decided to upgrade its insulation system with more than
10,000 square feet (929 m2) of Auburndale, Fla.-based Fi-Foil Co.
Inc.'s RetroShield System. Installed by Energy Home Shield of
Ocala, Fla., this exclusive system resulted in an approximate 15 to
20 percent reduction in monthly electric bills along with a cooler,
more comfortable building. This reflective insulating system sealed
off the air infiltrations, added an R-value of R-16 to the ceiling
and reflected 97 percent of the radiant heat away from the
building. And as an additional benefit of the simple installation
process, Iron Works did not have to close for this retrofit. The
owner is also able to maintain comfort at a 74 F (23 C) setting as
opposed to 72 F (22 C) prior to installation.
According to Iron Works Fitness Owner Terry Brasseale, he wanted to
find an affordable and efficient way to reduce his air-conditioning
costs. "Our electric bill was $5,400 during the month of July. I
had RetroShield installed in August, and our electric bill went
down to $4,700. By September, our electric bill had declined to
$3,400." Brasseale noticed another added advantage to having
RetroShield installed. "We've even noticed that the amount of dust
that accumulates on the gym equipment has reduced."
Matt Struss is corporate sales and marketing director for
Fi-Foil Co. Inc., Auburndale, Fla.
www.fifoil.com