A few months ago I had lunch with a friend of mine who recently bought
an older historic home in southern Ohio. The subject of insulation and
heating costs came up and we engaged in a bit of a debate over what kind
of insulation to use. Now, I don’t believe either of us won, primarily
because I don’t think an ultimately right answer exists for the topic
we were debating. The topic you ask? “How big of a role does the
R-Value really play in insulation on an application specific basis?” My
friend had bought enough R-30 fiberglass insulation for his attic
despite my attempts to encourage him to use a variety of materials, foam
and fiberglass included. Now, don’t get me wrong, fiberglass can serve
as an appropriate and effective insulation in a number of
circumstances. Fiberglass is good for walls, and can conditionally be
good for your attic as well. However, I view fiberglass insulation as
similar to a nice fleece shirt or pullover. They can certainly keep you
warm, but once the wind starts blowing, you feel it. In calm
conditions, fiberglass can work very well to keep heat in designated
areas, but does not excel as well as foam in preventing air movement,
and that air movement can contribute to a considerable amount of heat
loss. So what is the point of all this so far? Simple: Don’t assume
that just because your insulation has a high R-Value, that you’re going
to get the most effective results. My suggestion: If you want to use
fiberglass in your attic, that’s fine. However, be sure to go in and
use a good sprayed polyurethane foam around the exterior wall cavities,
fascia and soffit. Anyplace that air may be able to infiltrate from the
exterior (but remember that some ventilation is required). Once that
is complete, then you can add in any fiberglass that you’d like.
Remember, an R-Value is a measure of resistance to heat, not necessarily
a resistance to air movement. So the next time you’re looking to
insulate part or all of your home, just be sure to think carefully about
what you want to do, and keep an open mind about the different methods
available to reach that result.
Read more at our Hickory Energy Blog


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Comment by Mark Richardson on November 11, 2010 at 4:13pm
Great comments - I particularly like the "Fleece or Pullover" analogy. I'll be borrowing that one if you don't mind!

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