Weber County
Brigham City
Salt Lake


When the weather outside is frightful, rodents and other small animals may find the confines of your heating and cooling system delightful. Unfortunately, these unwanted visitors are far from good guests, especially when you consider the sheer amount of damage they can leave behind. It could take hundreds or even thousands of dollars to repair or replace an HVAC system damaged by pests.

The following takes an in-depth look at the type of damage an animal infestation can do to your HVAC system. You'll also learn what steps you can take to prevent that damage from happening in the first place.

1. Damaged Ductwork

Nesting animals may infiltrate your HVAC system's ductwork in search of shelter. Once inside, these unwanted pests can cause tremendous damage to your ducts. Animals can chew through flex ducts and fiberboard ductwork, leaving behind large holes and heavy debris while creating air leaks that rob your HVAC system of its performance and efficiency.

In addition, pests may bend, break, or otherwise damage sheet metal ductwork. More problems can result if the pest expires while it's still inside ductwork. Not only does the smell of a decomposing animal permeate throughout your HVAC system, but parasites, fleas, and various bacteria can also spread throughout the duct system.

As a preventative measure, you should have your HVAC professional carefully inspect your ductwork for any possible damage that could allow small animals to get through. They can repair and seal all cracks, gaps, and disconnects to prevent further damage.

2. Premature Corrosion

In addition to damaging your HVAC system's ductwork, rodents and other small animals can also leave behind urine and droppings. Animal urine is highly corrosive, so not only do you end up with bad odors throughout your ductwork, but your metallic ducts are also at risk of rusting or corroding prematurely.

In addition, urine and fecal matter can negatively impact other parts of your HVAC system, including the evaporator and condenser coils.
If you have to coax a critter out of your HVAC system, you should have a contractor inspect and thoroughly clean the system to prevent urine and droppings from corroding your unit from the inside out. You should also invest in an air purifier to remove any leftover odors and restore your home's indoor air quality.

3. Destroyed Wiring

Rodents and other small animals also have a tendency to chew through anything that gets in their way, including your HVAC system's wiring. If a small rodent encounters a bundle of wiring inside of your HVAC system's condenser cabinet, for example, it'll likely chew through the wiring and even strip away the plastic insulation as use for nesting material.

There's a good chance you won't realize what's happening until your HVAC system starts functioning erratically or ceases to function at all. Stripped wiring also poses a number of dangerous hazards. Without its protective insulation, a live wire could potentially arc against a metal component or another exposed wire, generating an arc or a short that damages your HVAC equipment while creating a potential fire hazard.

It's important to have your HVAC technician inspect your HVAC equipment's electrical wiring when checking for pests. If you're having trouble controlling your HVAC system or you notice a metallic, burning odor from your HVAC unit, you should shut the unit off and contact your technician as soon as possible.

4. Damaged Insulation

As unwanted pests make themselves at home in your HVAC system, they'll also search for nesting material. Unfortunately, the insulation located throughout your HVAC system makes the perfect nesting material for rodents and other small creatures. This insulation usually includes the foam insulation located around copper and aluminum refrigerant lines.

Without insulation, your refrigerant lines become more susceptible to freezing temperatures, resulting in potentially serious damage to your HVAC system. In addition, the insulation fragments can also spread throughout the HVAC system, leaving behind debris that could interfere with other components.

If you see chewed or otherwise damaged insulation, then chances are you’re dealing with an animal nesting inside of your HVAC system. After removing the animal, you should replace the foam insulation as soon as possible.

5. Blocked Exhausts

Birds, squirrels, and other small animals commonly make themselves at home inside of exhaust vents and air intakes, especially when your HVAC system hasn't been in use for some time. The problems come when you start to use your HVAC system again. For instance, combustion gases can quickly kill nesting animals, resulting in a dead and decaying obstacle blocking your exhaust vent.

Blockages can also pose a serious health and safety risk for your home. A blocked exhaust vent can easily result in a backdraft that allows combustion gases to flood back inside of your home, increasing your risk of carbon monoxide poisoning. Fortunately, the installation of a vent cover can help prevent small animals from getting inside of your exhaust and intake vents.

Homeowners are often surprised at the sheer amount of damage a small animal can cause when seeking shelter. Contact the experts at Dick Kearsley Service Center if you need your HVAC system repaired in the aftermath of an animal infestation.


520 S State, Clearfield, UT 84015

[email protected]

Hours Of Operation:

Mon-Fri: 8:00 am - 5:00 pm

Saturday: 8:00 am - 4:00 pm

Sunday: Closed

Find Us On:


Davis/Morgan: 801-773-4836

Weber County: 801-393-1265

Brigham City: 435-553-4556

Salt Lake: 801-292-1636


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