Insulation Can Make Your Home Healthier and More Energy
Efficient
Know the Real Value of R-Value
With energy costs taking such a huge bite out of the monthly
budget, it’s little surprise that energy efficiency
is the top consideration among those who are building or
remodeling a home, according to a recent survey by the NAHB
(National Association of Home Builders) Research Center.
The typical U.S. family spends close to $1,500 each year
on energy bills, almost half of which covers heating and
cooling costs (Source: Energy Star).
If you’re building, renovating or just thinking
about improving your home, there are few better ways than
the right insulation to enhance the energy-efficiency, comfort
and even health of your home. The right insulation can pay
for itself in monthly energy cost savings, can eliminate
hot or cold spots in your home, can help control moisture
problems and improve indoor air quality.
Nonetheless, installing insulation is a considerable investment
and the decision-making process can be overwhelming. There
are dozens of products on the market, none of which you
can take for a test-drive or return once installed.
So how do you choose the right insulation for your home?
This question helps explain the enduring popularity of R-Value
as a standard for comparing the energy efficiency of insulation.
R-Value helps us "compare by numbers" in that
the higher the number, the better the insulation is at reducing
energy loss. By this measure, you might assume that an R-40
insulation should be far more effective than an R-20 insulation
- right? The truth is, there are some good reasons to think
beyond R-Value when shopping for insulation.
A leaky story
To start, what is R-Value? R-Value was created to measure
the thermal resistance to heat flow offered by traditional
insulation (conductive flow) in a controlled laboratory
setting. What it doesn’t consider is that, in a real
home, heat (and money) also flows in or out through radiation
(energy in waves) and convection (air leakage).
You might also think that increasing insulation R-Value
provides a proportionate increase in its ability to control
energy loss. In reality, an R-8 insulation already controls
90 percent of potential energy loss through a material (Source:
Fourier’s Law of Thermodynamics). Upgrading from R-8
insulation to R-32 insulation, for example, would reduce
conductive heat flow by only another seven percent (assuming
no air can move through the insulation).
The real problem is heat loss through convection (or air
leakage), which accounts for as much as 40 percent of the
total energy lost by your home (Source: U.S. Department
of Energy). And even the best conventional insulation on
the market won’t control air leakage - regardless
of R-Value.
So, if R-Value doesn’t provide the help we’d
like in comparing insulation, what will? The best strategy
is to make a well-informed choice, by knowing the factors
that will affect how well insulation performs in your home.
If you are building, remodeling or just thinking about adding
insulation, ask a builder, contractor or anyone providing
information about insulation products the following questions:
Ten important questions to ask about insulation
…that take performance beyond R-Value
- How well does the insulation control air leakage that
can account for up to 40% of a home’s energy loss?
(spray foam insulation such as Icynene is particularly
effective at creating a continuous air barrier)
- How quickly will the insulation pay for itself? (are
the monthly energy savings greater than the monthly cost
of financing the insulation purchase?)
- How well does the insulation reduce air leakage in hard-to-insulate
areas such as rim joists, cathedral ceilings, crawlspaces,
garages, etc?
- Can the insulation help reduce heating and cooling loads
(and costs) while removing the need for larger/costlier
mechanical equipment?
- Will the insulation help keep out allergens, dust and
other pollutants?
- Will the insulation shift with the home over time as
it settles? Will it leave spaces, gaps?
- What happens if the insulation gets wet? Will it keep
its insulating properties? Can it grow mold?
- Does the insulation contribute to poor indoor air quality?
- Can the insulation help control sound (around plumbing,
between rooms, from outside)?
- Does the insulation require a number of finishing materials
(plastic wrap, gaskets, tape) to eliminate gaps or cracks?
Note: A builder/contractor/sales
person should be able to answer most of these questions
and provide insulation options that can help your home become
more energy efficient, healthier, quieter and comfortable.
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