What is R-Value?
R-Value
is a measure of how well an insulation product resists heat or cold. The R-Value is the
result of a laboratory test in which an insulation material is sandwiched between a cool
and warm surface. The ability of the material to resist these temperature differences
results in an R-Value for that material.
So what's wrong with that?
A machine in a laboratory gives a relative number that can be used to compare products,
but a laboratory R-Value does not tell everything you need to know. Insulation is
subjected to a wide range of temperature conditions in a house. The insulation is affected
by air movement, and it is also degraded by the convection forces that develop within the
insulation material. This loss of R-Value by natural forces is common with lightweight
insulation products.
The "Colorado Study":
The University of Colorado School of Architecture tested the "real world"
performance of cellulose and fiberglass 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 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 three weeks of monitoring the
cellulose building 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".
|
The Oak Ridge National Laboratory Test:
Researchers at Oak Ridge National Laboratory (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 products declined
as much as 40% in R-Value as the temperature difference between conditioned (inside) air
increased and the ambient (outside) air decreased. Bottom line; when the temperature in
your attic is 20 degrees the fiberglass insulation in the attic has lost 40% of its
R-Value. The researchers at ORNL recommended that people who have attics with fiberglass
insulation cover that insulation with as little as 3 inches of cellulose to stop the loss
of R-Value in the fiberglass.
Guaranteed Energy Program:
If all insulation materials were equal NU-WOOL COMPANY could not guarantee
the energy costs of homes using the NU-WOOL process. For the past nine years NU-WOOL has
offered a free guaranteed energy program for anyone requesting the service. In that time,
thousands of homes have taken advantage of this program.
How does it work?
Each home's characteristics are entered into a computer program that
calculates heating loads and the cost of heating based on fuel, weather data, efficiency
of the heating system, and the air infiltration factor for that home. If only R-Values was
used in the computations, homes with NU-WOOL insulation would not heat any differently
than homes with fiberglass. Through decreased air infiltration, cellulose insulation has a
higher "effective R-Value"; cellulose homes heat more efficiently than
traditionally insulated homes.
|
