Why does it sound like something is in my vent?

Author: Claudia Harris  |  Last update: Wednesday, July 2, 2025

Rattling, thumping, or grinding noises likely mean there is a problem with your ducts. This could either be a simple problem, like dirty air filters or a blocked vent. Or it could be something more severe.

Why do I hear something in my vent?

Poorly installed ductwork can increase the velocity of air moving through ducts, which can cause noise. Also, flexible ducts can sag or twist if they aren't installed correctly, making it harder for air to move through them. As a result, pressure can build up inside the ductwork, and lead to a noisy air vent.

What animal could be in my vent?

Mice and Other Rodents

But on occasion you may be dealing with squirrels or even rats. There are a number of ways they may have gotten into the ductwork. But they started their journey to the ducts by entering the house first. Once in the house they may have entered the air ducts via the HVAC unit in the basement.

How do you know if something is in your vents?

If rodents have set up house in your ducts you should notice some or all of the following signs.
  1. 1: A Rancid Odor. ...
  2. 2: A Scraping, Gnawing Sound. ...
  3. 3: Insects Coming From Your Supply Vents. ...
  4. 4: An Uptick in Allergy Symptoms. ...
  5. 5: Damaged Ducts.

What do mice in vents sound like?

What do mice sound like in vents? When mice are in your vents, you'll hear scratching, crawling, or scurrying on metal in the walls, ceilings, or floors where your ductwork is.

5 Common AC Noises and What They Could Mean

How do I get rid of rodents in my vents?

Switch off your central heating and cooling system and let the grates reach room temperature. Unscrew and remove the grates that cover your heat vents. For each vent, bait a snap trap with the fragrances of fetching foods, such as raisins, dates, cheese, chocolate or peanut butter.

What smells do mice hate?

Some of the smells that mice hate include:
  • Peppermint oil. Peppermint oil is a natural repellent that can be used to keep mice away. ...
  • Cinnamon. Cinnamon is another natural repellent that mice hate. ...
  • Vinegar. The pungent smell of vinegar is also effective at repelling mice. ...
  • Citronella. ...
  • Ammonia. ...
  • Bleach. ...
  • Mothballs.

What could be crawling in my vents?

Air vents that aren't properly sealed off can be attractive entry points for rats, mice, and other rodents. The smaller the rodent is, the more places it can roam about your home without being spotted. If you notice rodent droppings but can't find them, you may have some rodent residents in your air ducts.

How often should ducts be cleaned?

Experts advise having your air ducts cleaned every 2 to 3 years to prevent many maintenance and health problems before they start. However, homes with pets or children with allergies should have their air ducts professionally cleaned more frequently than the recommended average.

How to tell if an animal is in an air duct?

Identifying Signs of Animals in Your Air Ducts
  1. Strange noises: Scratching, scurrying, or squeaking sounds from your air ducts are often one of the first signs of an infestation. ...
  2. Foul odors: If you notice unpleasant odors coming from your vents, especially when your HVAC system kicks on, you might have animals in there.

How do you get an animal out of your vents?

If you suspect that there are animals, either living or dead, in your air ducts, it is best to call a professional to lure the animal out or remove the animal carcass. Employing a professional protects your safety and home by causing the least amount of damage possible.

Why do my ducts make noise at night?

Possible Causes of Ductwork Noise

The most common reasons to hear noise in your HVAC ducts include: Air Pressure: A buildup of pressure can cause rumbling sounds. It can also cause the metal to expand and contract.

What does a dead animal in ductwork smell like?

One of the worst things that can happen to your HVAC ducts is having a dead rodent get trapped inside. As its body starts decomposing, it will emit a rank odor that permeates the entire house.

Is there an animal in my vent?

Signs there's an animal stuck in your AC

Confirming that there are rodents in your air ducts is pretty easy: If they're alive, you'll hear scratching sounds inside your walls or above your ceiling as they scurry around (*shudder*).

What does a clogged vent pipe sound like?

How to tell if the vent pipe is clogged? Common signs of a clog you can look for include slow-draining sinks and toilets, foul smells lingering in your home, or a gurgling sound in your drains.

Why do I hear something when I breathe?

Air flowing smoothly through your airways creates normal (vesicular) lung sounds. Swelling, blockages or mucus in your airways can create abnormal lung sounds. These include rhonchi, wheezing, stridor, crackles (rales) and pleural rub.

Can I clean my air ducts myself?

Use a brush to loosen any buildup of dust in the ductwork. Lift register and insert vacuum hose as far into the piping as it can go. Turn the vacuum on to capture as much dust as possible that the fan is pushing through the ductwork.

How expensive is duct cleaning?

Typically duct cleaning ranges from $450 to $1000 and is highly dependent on the situation and the type of services you need.

How do you tell if your ducts need cleaning?

If you see dust and dirt both inside and outside — especially by the vents that blow cool air out — your ducts most likely need to be cleaned. To prevent future dust buildup, make sure you replace your HVAC system air filters frequently. You can also run an air purifier.

What do rodents in vents sound like?

The sounds they make:

Rodents are known for their swift movements, so if the scratching sounds are accompanied by scurrying sounds, you're likely hearing a rat or mouse on the move. Rodents chew and they chew loudly and persistently.

How do you tell if your vents are clogged?

Signs of an air duct clog include: One room in your house is hotter than all the others. Dirty air coming from vents. Unusual spikes in electric bills.

How do you get bugs out of air vents?

Keep the Air Vents Clean

Additionally, thorough enough cleaning will encourage the bugs that already live in your AC vents to leave. Removing all dirt and debris and covering the walls in robust cleaning solutions will make that area uninhabitable instantly, even if there were bugs previously living there comfortably.

What kills mice asap?

Zinc phosphide is an acute toxicant that causes the death of a house mouse within several hours after a lethal dose is ingested. It appears to be the fastest way of getting rid of mice by reducing their population.

Will mice leave if they smell a dog?

Mice have a very sensitive sense of smell, and if they sense the smell of a predator, they are much more likely to avoid the area. However, mice do not seem to be afraid of dog smells or their fur.

Will spraying vinegar keep mice away?

Plus, vinegar isn't always effective at keeping rodents away. While the smell may irritate some, others bypass it completely to reach food. To combat the mice problem in your home, you'll need to rely on proven pest control methods to eliminate pesky pests.

Previous article
What is replacing 410A refrigerant?
Next article
Where do you put vapour barrier?