Adding
Insulation to an Existing Home
Unless your home
was specially constructed for energy efficiency,
you can usually reduce your energy bills by
adding more insulation. Many older homes have
less insulation than homes built today, but
adding insulation to a newer home may also pay
for itself within a few years.
To determine
whether you should add insulation, you first
need to find out how much insulation you already
have in your home and where.
A qualified home
energy auditor will include an insulation check
as a routine part of a whole-house energy audit.
An energy audit will also help identify areas of
your home that are in need of air sealing.
(Before you insulate, you should make sure that
your home is properly air sealed.)
If you don't
want an energy audit, you need to find out the
following:
- Where your
home is, isn't, and/or should be insulated
- What type
of insulation you have
- The R-value
and the thickness or depth (inches) of the
insulation you have.
If you live in a
newer house, you can probably find out this
information from the builder. If you live in an
older house, you'll need to inspect the
insulation yourself if you don't want an energy
audit.
Inspecting and
Evaluating Your Insulation
- Check the
attic, walls and floors adjacent to an
unheated space, like a garage or basement.
The structural elements are usually exposed
in these areas, which makes it easy to see
what type of insulation you have and to
measure its depth or thickness (inches).
- Inspect the
exterior walls using an electrical outlet:
- Turn
off the power to the outlet.
- Remove
the outlet cover and shine a flashlight
into the crack around the outlet box.
You should be able to see if there is
insulation in the wall and possibly how
thick it is.
- Pull
out a small amount of insulation if
needed to help determine the type of
insulation.
- Check
outlets on the first and upper floors,
if any, and in old and new parts of a
house. Just because you find insulation
in one wall doesn't mean that it's
everywhere in the house.
- Inspect and
measure the thickness (inches) of any
insulation in unfinished basement ceilings
and walls, or above crawl spaces. If the
crawl space isn't ventilated, it may have
insulation in the perimeter wall. If your
house is relatively new, it may have been
built with insulation outside the basement
or foundation walls. If so, the insulation
in these spaces won't be visible. The
builder or the original homeowner might be
able to tell you if exterior insulation was
used.
- Once you've
determined the type of insulation you have
in these areas and its thickness (inches),
see the U.S. Department of Energy's online
Insulation Fact Sheet for how to determine
the R-values of insulation previously
installed in your home.
Determining
Recommended R-Values
When you find
out the R-values of your insulation either from
an energy audit, the home builder, or your own
inspection, you can then use the U.S. Department
of Energy's
Zip-Code Insulation Program to determine how
much insulation you should add and where to
achieve the recommended insulation levels for
maximum energy efficiency. To return to this
page, click the back arrow.
Deciding What
Type of Insulation to Add
If you decide to
add insulation to your home, review our
information on the
types of insulation available to help you
decide what type to use and where.
U.S. Department of Energy -
Energy Efficiency and Renewable Energy
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