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Duct Blaster
Testing ducts for leakage is probably one of the most important
functions we can provide. Duct leaks can account for almost half of
your cooling/heating loads.
To test duct work we temporarily seal
off every supply and return in the system. We the hook up a small fan
to one return, and pressurize the ductwork to 25 pascals. To maintain
a steady pressure we know that all the air entering the system must be
escaping through leaks. Using the manometer, we can see how much
air in cubic feet per minute is being pushed into the system. We have
seen ducts leak more then 75% of there designed air flow !
Now leaks are never good, but some are
far worse then others.
Ductwork may run above your first floor ceiling, and leak to your
second floor.
You may have leaky ducts in a wall where the leak enters the room
through a switch plate. These leaks are considered leaks to
conditioned space and cost less, but can create comfort issues in
rooms that are short changed.
Measuring leakage to outside conditioned
space requires a blower door in addition to the duct blaster. The
blower door is set now to pressurize the home to 25 pascals while the
duct work is being pressurized to the same 25 pascals. Now any leaks
to conditioned space is canceled out by the blower door and the duct
blaster will only show leaks to unconditioned space !
Once the measurements have been made we
can decide on an approach for repairs.
Typicaly we will always try to seal leaks closest to the air handelr
as the pressures will always be higest at these areas. Near the
handler, a hole that measures 1/8 of in inch wide may leak 15 times as
much as the same hole near the end of a run. Ultimatly we would always
want to seal up the ducts so that the leakage measures zero, but in
real life is usualy unpracticle.
BPI has set standards, typicly we can allow no more then 10% of the
verified system flow in a total loss test. This is what we try to
achive on every job.
If you have any suspisions that your duct work is leaking, stop
throwing your hard earned money out the window and give us a call !
rec-hers@optonline.net
Residential Energy Conservation
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3771 Nesconset Hwy |
Suite 101A |
S. Setauket NY 11720
631-751-7911
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