Critter in Heat Duct

JWLuckDecember 22, 2012

Hello all -
This is more a pest in the HVAC system problem (didn't see pest forum, so apologize if I missed it). I have a gas furnace in the basement that feeds to several registers in our single story home. In the last couple months, some nocturnal critter has been scratching furiously beneath a heat register in the furthest (from furnace) part of the house, where the crawl space has least clearance (i.e, the part I can't get to). I popped the register and duct boot was hanging beneath the cutout by a few inches, pulled from the floor. I re-nailed it shut and thought the problem was briefly solved. I also found that a nearby foundation vent had a hole a few inches wide in it, and sprayed foam to seal it.

Nope! The scratching came back at night - but intermittently (1-3x/week). Sounds like something is furiously trying to scrape through the register into the home. Now, little to no heat comes out as well. I believe the critter must have torn some holes in the ductwork based on this. I also cut some hardware cloth and closed the foundation vent again - the critter had scratched/chewed its was through all the foam and the gap was even widened to about 5"across - and left a basement door open at night as an exit.

I know a skunk was living under there this past summer to Fall, possibly making it its den and breeding. Haven't smelled it in last couple months.

Question - does this sound like a skunk (size of hole, nocturnal, known presence)? If so, why would the skunk be obsessed with the duct/heat register? Would they den inside the duct?? Other thought is could be a rat but haven't seen evidence of this...thoughts?

OK - this was quite a rant. Sleepless nights.

(PS-Oakland in SF Bay area)

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    Bookmark   December 22, 2012 at 4:44PM
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they like the ducts because they are warm.
if it gets in the duct as your title says
then you find the hole it made to enter.

if the insulation is missing around the supply may be comming for the water.
if the crawlspace is cold, the supply box
is metal and warm air is moving in the
supply will condensate.

may either be a thirsty critter
or a cold one.

find hole(s) seal with critter resistant
material. sheet metal, flashing..depends on
where the hole is located.
knowing what type of duct work you have
will help to advise you on how to seal.
can you take a picture of the access hole
you've sealed? and take the supply grill
off and take a pic inside the supply box
so we know what you have. its hard to see
from here.

if someone installed the duct to this
area..there is some type of access.
get a piece of plastic, lay on it
and scoot around to see what is going
on under the house.

it could be a racoon, armadillo, possum,
skunk..lots of critters out there.
luckily it probably isn't a zombie.

best of luck

    Bookmark   December 22, 2012 at 7:20PM
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