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Dangers of Animals and Your HVAC System

June 17, 2022
Rodents in AC

While small and medium-sized animals are cute, they can also wreak havoc on your HVAC system. Unfortunately, they may cause hundreds or even thousands of dollars in repair or replacement costs. Here’s a closer look at the different types of animals that may make their way into your HVAC system and what types of damage they might cause.

Mice and Rats

Rodents like mice and rats love to crawl into tight spaces and can really take a toll on your HVAC system. Most of them are notorious for chewing on your insulation, sealants, and wiring. They’ll try to nest inside the air ducts, causing pollution from rotten food droppings and other bacteria. Plus they might prompt an electrical fire when they nest or cause your entire HVAC system to fail.


Due to their unique shape, cockroaches can squeeze through just about any small crack or hole. Since they thrive in cool, dark places, don’t be surprised if you hear them move through the ductwork. Even though they're unlikely to cause much damage, they do carry diseases and bacteria so it’s important to get them out of your house.


Spiders are similar to cockroaches in that they find their way into tiny areas. There’s a good chance they’ll get into your ductwork, vent, and indoor air conditioning unit, especially if you don’t keep them cleaned and maintained. Spiders are also a health hazard due to their harmful venom.


Since they’re cold-blooded, snakes look for warm shelter when it’s cold outside. They may even nest in ductwork and breed there as well. It’s also quite common for snakes to get into condenser units. When the fan turns on, the snake usually dies and will likely damage the blades and other HVAC parts.

Signs Your HVAC System Has Animals

If you notice foul odors from an animal’s nest or dead animals, your HVAC system is likely infested with animals. Also, you may hear noises from the ceilings, walls, and below the floor where your ductwork lies. Another common sign that there may be an animal or two in your HVAC system is holes that make it easy for animals to enter.

How to Prevent Animals From Entering Your HVAC System

By being proactive, you can prevent animal-related damage to your HVAC system. First, seal up any holes around your home. Then, repair any gaps, holes, or disconnected sections in visible ducts near your crawl space, attic, and basement. Don’t forget to securely cover your exhaust vent so that animals don’t use it to enter your home. Lastly, invest in a routine inspection from an HVAC professional that can uncover any issues and resolve them.

Change Your Air Filters Without the Hassle

We are pleased to offer quality air filters that can capture pollutants and particles, pushing clean, fresh air back into your living space. For the filters to be most effective, however, you must change them every few months.

With FilterTime’s air filter subscription service, you can keep the air in your home in optimal shape, year-round. Once you subscribe, the right air filters will get shipped to your doorstep automatically so you’ll know exactly when to change them. Since there are no shipping charges, contracts, or hidden fees, you have nothing to lose. Get started today!

Written by: Anna Baluch 

Headshot of Writer Anna Baluch

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