WHAT
IS EFFECTIVE ‘R-VALUE’?
Why is this term is important
when deciding which insulation is right for your enclosure…
Relating to standard construction, not glass enclosures
R-Value
is the measure of how well insulation
products resist cold or heat. R-Value
is the result of a laboratory test
in which an insulation material
is sandwiched between a cool and
warm surface (before your install
your Vapor Barrier) for your room.
The better or higher the R-Value,
the better the insulation and lower
heating & cooling costs for
your room.
SO
WHAT’S WRONG WITH THE LABORATORY
TEST?
A machine in a lab gives you a RELATIVE NUMBER that can be used to compare
products, but a laboratory R-Value does not tell you everything you need
to know. Insulation is subjected to a wide range of temperature conditions,
depending upon geographic and climate differences where the building
is located. Air movement affects the insulation, and the convection forces
that develop with the insulation materials also degrade it
THE
COLORADO STUDY
The University of Colorado School of Architecture tested the REAL WORLD
performance of cellulose vs. fiberglass batt insulation. They built two
structures and insulated one with fiberglass using R-19 in the walls
and R-30 in the ceiling. The other structure had the same measured R-Values,
but was insulated with a blown in cellulose insulation. The cellulose-insulated
building was seven degrees warmer than the fiberglass structure after
a nine hour heat loss test. But more importantly, after 3 weeks of monitoring
the cellulose building, it used 26.4% less energy than the fiberglass
structure. The researchers concluded that cellulose performs 38% better
than fiberglass insulated structures. Keep in mind that both structures
had the same measured “R-Value” but cellulose has a higher “EFFECTIVE
R-Value”. This is due to the fact that cellulose or blown in, blown
on insulation is air tight.
THE
OAKRIDGE NATIONAL LABORATORY TEST
Researches at ORNL tested insulation under “real” conditions in a
full scale attic simulator. The temperature of this simulator can be varied to
reflect different temperature conditions, just like the temperatures a house
experiences. Their research found that fiberglass product declined as much as
40% in R-Value as the temperature difference between conditioned (inside) air
increased and ambient (outside) air decreased. Bottomline: when the temperature
in the attic is 20 degrees, the fiberglass insulation in the attic space has
lost 40% of its R-Value. The researchers at ORNL recommended that attic spaces
with fiberglass insulation be covered wit as little as 3 inches of cellulose
to stop the loss of R-Value in fiberglass.
It
is extremely important within a
pool environment to utilize good
insulation and prevent cold air
infiltration, so that
the heat loss/heat gain is kept
to a minimum, and to help prevent
condensation from forming when
warm meets cold. Good airtight
insulation is important for reducing
air infiltration and heating and
cooling costs. EPS recommends for
residential projects a minimum
R-19 Wall, R-38 Ceiling. If using
fiberglass bat, foam and/or seal
all major cracks and crevices where
cold air can infiltrate to the
warm side of the building.
EPS is the home of DRY-AIR & VERI-DRY. We provide Design, Engineering, Consulting and Manufacturing for Residential and Commercial Indoor Swimming Pool Applications.
