An Overview of Insulation R-Values
Without adequate insulation, many areas of a home will not be energy efficient.
It is generally known that heat always flows from warmer to cooler surfaces, and
the flow does not stop until the two surfaces have equal temperatures.
Insulation mainly resists the flow of heat, and because this heat flow is
reduced, a properly insulated home uses less energy for heating during winter
and also less energy for cooling during summer.
In addition to saving energy, insulation makes an excellent sound absorber,
reducing the transmission of sound. when installed in walls and ceilings. Thus,
homes constructed with the latest home insulation products, appliances, doors,
windows, lighting and heating/air conditioning equipment will tend to be more
energy efficient.
Definition of R-value
Insulation is identified and labeled by a unit that relates to the transfer of
heat through conduction, which is called an R-value, where "R" stands for
resistance to heat flow. The more heat it can resist, the higher the R-value,
and vice versa. So it is always recommended that insulation should be purchased
based on its R-value, and not its weight or thickness.
What You Need to Know About R-Values
Different types of house insulation materials have different R-values. The
R-values for house insulation will vary based on climate and temperature, and
are usually lowered when air or moisture leaks are present. Performance testing
of R-value is done in temperature environments of at least 70º F with no air
movement. For basement insulation, the average recommended R-value of insulating
material is R-12.
Being thicker or thinner does not affect a material's R-value; if two different
materials have the same R-value, they should provide equal insulation, no matter
their thickness. A basis of comparison would be one inch of insulation equals
about 30 inches of concrete.
Home Insulation R-values
1. Clear wall R-values refer to the R-values of a wall with its studs, not
including its frames, doors and windows.
2. Center of cavity R-values refer to the estimated cavity space area between
the studs.
3. Whole wall R-values refer to the R-values of the wall system and center of
cavity. Whole wall system indicates all materials used like doors, windows, and
exterior corners. This is a known reliable method for determining R-values of
wall insulation.
|
