Critters in my HVAC duct work!

No idea what but we hear them scratching or scampering only at night.

They have to have access as we have heard them almost nightly for a month… they need food and water I would think. Obviously don’t want to poison them and have them die in the ductwork!!!

The house crawlspace is closed and should be pretty critter proof, brick house.

I thought about some of those natural critter repellents and using a garden sprayer to spray down all the vents as far as possable, hoping it would run them off. The manufacturers claim they have a pleasant smell for humans and are offensive only to the critters. However, reviewers say it really doesn’t smell good.

My wife is going on a three day trip so I thought I might try it during that time in case it did really smell bad in the house . Really too hot and humid for this old softie to go without AC this time of the year.

I kinda doubt that the HVAC guy or an exterminator either one would have much luck with the problem

Any suggestions….

Oh… they cannot be heard in the return duct, only the supplies and only at night. We have a conventional heat pump, one piece outside unit. Duck work in the crawlspace.

Yeah, I would agree, if they are in the ductwork, they have to have an enter/exit point (as in a hole) to eat and drink.

I would have a ductwork guy come and inspect first, then an exterminator to lay some traps. Unfortunately, it is prob a vicious circle of rinse and repeat til you get them all.

Maybe there is a poison you can put out that makes the varmints seek water, therefore gotta leave the ductwork.

You'll prob be able to tell if you catch something...at least a few days from its demise!!!

You could also try one of those 5 gallon bucket water traps if it will fit in the crawlspace.

https://www.amazon.com/Bucket-...aps%2C99&sr=8-5&th=1

Do you have any flex duct or is it all hard pipe?

if it were me, I'd put a little granola there and a camera in front of the granola to see what's you've got.

Squirrels. Trap outside with peanut butter. Destroy or relocate. Continue until noise vanishes. Hope you don't have a bunch of baby squirrels in a nest, as they will die in the duct without a mom.

They could be scratching or walking on the outside of metal duct work and it would sound like they are inside.

quote:

Originally posted by 220-9er:
They could be scratching or walking on the outside of metal duct work and it would sound like they are inside.

Thought of that… ducts are externally insulated with foil covered fiberglass.

Since we only hear them at night after dark, does that mean they are nocturnal or are they just coming home to roost at night?

I think all ducts are rigid metal.

We know to have seem
Mice
Moles
Chipmonks
Squirrels
Possum
Skunk
Armadillos
Fox
Coyotes
Skunks
On our 4 acre.
The cat generally keeps the smaller of those killed out, olong with the lizards and snakes.

Can’t bring myself to shove her in the duct!


I have a camera I may deploy…

If you set traps in the ductwork tie them off to something so the critter doesn't pull the trap deep into the maze.

We had flex ducts under our home in NC. Mouse knawed in. Then proceeded to eat the stuff I put down the drain for the septic. I could tell when the poo turned blue, then I knew what I had. Took forever to figure out where he got in. I put tomcat blocks under the house and on every pier. That took care of it.

I’d think they have to come & go from the ducting, can’t just live in there.

I’d check around best you can, looking for scat/poop, sign, chewing. Most likely it’s mice, could be something else.

Most ‘exterminating’ companies put pet proof ‘bait houses’ in likely areas. Electronic killing traps are an option.

Most houses and/or buildings need a preventative program to keep rodents out. I have two bait houses on the perimeter, with an additional covered box to make it even more pet proof.

I’d hire an exterminator that does this all the time. No point in reinventing a wheel.

A wood rat will come at night to steal the fiberglass insulation.

Well Im giving this a go. Not very hard or expensive.

Balls ($1.00 each) came with little pouches. I doubled them up and put two in each pouch. Tied a string on them in case of need to retrieve/replace and put one down all 14 vents. There were two I could not get to easily.

After putting them in I closed all the vents up and turned off the HVAC unit... until it gets too hot to hopefully saturate the duct work with the scent. They smell about like like peppermint.

Also put two in both return grills.

quote:

Originally posted by cparktd:
Since we only hear them at night after dark, does that mean they are nocturnal or are they just coming home to roost at night?

I think all ducts are rigid metal.

We know to have seem
Mice
Moles
Chipmonks
Squirrels
Possum
Skunk
Armadillos
Fox
Coyotes
Skunks
On our 4 acre.
The cat generally keeps the smaller of those killed out, olong with the lizards and snakes.

Can’t bring myself to shove her in the duct!


I have a camera I may deploy…

Google flying squirrels. Only active at night. Had some in my attic a few years ago and put a rat trap loaded with peanut butter up there. Didn't know we even had flying squirrels in our area until I caught the first one.

https://www.tn.gov/twra/wildli...flying-squirrel.html

Little update
Well I don’t want to jinx it but we haven’t heard them/it yet a single time since I deployed the repellent… so nothing heard in a week. The longest it has gone previously without hearing them is two nights one time, and one night to other times, so I’m encouraged.

Inspect all the ductwork. If they were in it. There’s a hole someplace. I had to replace a bunch

If you can post some pics of any found droppings I can tell you what it is. Could be mice or southern flying squirrels. How loud is it? Light and scratchy or does it sound like something larger walking around in there?