[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: GBlist: Weatherization-Insulation as if People Mattered



Fred Lugano wrote:
 
> Read "Fixing a Cold, Drafty House" in Fine Homebuilding #105 (Nov96)for
> a primer. You will find that all of the factors that dominate building
> performance are located in the basement and attic. Wall insulation is at the bottom of the list for upgrading a thermal envelope.

I have to disagree about the importance of insulating the walls of the
thermal envelope.  Yes, the top and bottom of the building are very
important for convective heat loss through air leakage.  But the walls
cover significantly more surface area than the floor and attic and are a
*major* source of conductive heat loss.  In addition, wall cavities act
as excellent chimneys and facilitate the movement of air if there are
openings at the top and bottom, as there usually.  Filling the cavities
tight stops this pathway.  It is not uncommon to find a 30%-50%
reduction in air leakage, as measured by a blower door, after a home has
been dense-packed with cellulose.

Columbia Gas of Ohio has done evaluations of pre- and post- retrofit
savings of measures installed by their weatherization program.  They
have found consistently high savings for sidewall insulation.  In
addition, occupant comfort is increased due to higher surface
temperature of the walls.  BTW, they've also found consistently low
savings for basement ceiling insulation retrofits, although they're not
sure why (there are many possible factors).

Ohio does have a good weatherization network.  Many of the agencies and
contractors are looking for private business, now that the HWAP program
has been cut back.  I have scanned walls insulated with dense pack
cellulose by weatherization crews and they've looked great (warm), even
with a blower door running.  The key is finding a contractor that truly
knows how to blow a wall tight.  

Michael Sherman wrote:

> The house currently has no insulation in most walls in north east Ohio, USA (HDD base 18.3C = 3445).

Columbus, Ohio, where I worked until recently, has about 5600 HDD.  Your
area in north eastern Ohio probably has even more, increasing the cost
effectiveness of going for wall insulation.  Let me know if I can help
you locate a contractor.

-- 
Catherine M. Muller
National Center for Appropriate Technology
614/767-9000 (phone); 614/767-9033 (fax)
cmuller@ncat.org

__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________


References: