To many homeowners, central
forced-air hvac systems spell the
ultimate in comfort. However,
buyers don't know, and contractors
are just learning, that the comfort
and efficiency of a central hvac
system often come with an energy
penalty. Recent research shows that
ducts are responsible for 20% to
60% of the air leakage in houses.
Some contractors have used duct
tape to seal ducts — seemingly a
logical move — but duct tape
becomes brittle and loses its
adhesion within a couple of years.
So more residential contractors are
turning to the treatment used in
many larger commercial buildings
— duct mastic. Applied properly, it
can all but eliminate air leakage
from ducts.
Duct mastic doesn't hold ducts or
their seams together. That's