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Ants coming out of A/C vents

55647 Views 11 Replies 5 Participants Last post by  acewazup
I have A/C vents in the floor (ductwork goes through the crawlspace), and have had problems recently with the ants coming out of the vents. It appears that they're living in the gaps between my flooring, and using the vents as the point where they crawl out. I've also had some come out of wall outlets. Any suggestions on dealing with this, other than spot-treating?
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Ive had good luck with terro liquid ant bait, from HD. It's boric acid disolved in sugar. They feed it to the queen as well.
You could use aluminum tape around the registers to prevent them from coming in around the duct itself. Use mastic and tape to seal the ducts if you don't want them in there. Then use boric acid mixed with sugar or peanut/butter grease for many types of ants placed in the crawl space and around the house. But first thing you want to do is figure out what type of ants you have. Are they sugar ants, carpenter ants, etc.

Also, try to keep your house clean and dry so the ants have no food to come looking for. Most ants don't want to be in your house, but some will nest in and/or eat your house.
It definitely seems like they're just nesting in the house– we mostly see them outside, and haven't ever seen them leading to any food sources in the house.

They're definitely sugar ants. I'll take the advice on trying to seal up the gaps. Thanks!
Noquacks hit the nail on the head. Boric acid. I mix it with slightly watered down honey or syrup to get their attention. You want the ants to get it, not stick to it. They will take it back to the nest where others will enjoy the treat. Boric acid works from the inside out. It's abrasive to the ants exoskeletons and kills them.

Never, ever, ever spray, as ants will split and form another colony. I can't stand the thought of them in the house. You can't use the boric acid alone in the a/c vents as it is powder form, but try to get it as close as possible to the nest. Your goal is to kill the queen. I found it very satisfying one night when I had to get up to use the bathroom and found queenie staggering around on the bathroom floor. I put her out of her misery.

Every two months I'll place the boric acid around the water pipes that come up through the floor or anywhere else they might try to get in. A ants needs will change come fall. The will take the sugar it's all they can find, but they also go through a starch phase. I'll then mix it with corn meal.

Boric acid is only poisonous if taken internally or inhaled in large quantities, but it's still toxic, so take into consideration children and animals. It's cheap and can be purchased in some grocery stores. It will not kill fire ants.

It took about 5 days until I saw the last one. Three months later I figured out where they were coming in. They came in next to a tiny hole at a water spigot, climbed the copper pipe and disappeared into the subfloor. I moved a piece of wood near the copper pipe they were using and there had to be a million dead ants that fell off the copper pipe.

Best of luck to you!
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Thanks so much for your advice everyone! I really appreciate it and have ordered some boric acid so we'll see how it works!
Thanks for the confidence, Missy. But remember, technical difference between dry boric and dissolved boric acid. I do not bother with the dry. The ants need to INGEST the boric in the guise of the sugary mix. Also, a tech point- boric solution (sugary mix) does not work by drying out their exoskeletons, but by systemic toxicity once ingested.

You may be confusing the "drying out" with the affect when using diatamaceous earth.

Dont buy dry boric. Different effect. Likely the queen will not be affected.
You're saying not to buy dry boric? Can't you just mix it with a liquid of your choice to make dissolved boric? You're saying to buy a liquid boric acid? I've never seen that. Sounds like you'd be paying for added water.
I think what noquacks meant was not to treat the ants with dry boric acid. I believe this works for roaches, because they pick it up on their legs, but not with ants.

I ordered it online from Walmart and had them ship it to the local store– I couldn't find any actually in stock in the store, and walmart's price was about 1/3 of what amazon listed it for. Here's the link to what I ordered:

But anyway, I plan on mixing up the boric acid with either sugar water, or even peanut butter– some sites said different ants like different things.
The same ants may want sugar or grease depending on the needs of the colony. So test out both and see what their craving.
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