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