The Casteel Amazing Care

Rodent Damage Taking Over Your HVAC? Learn How to Fight Back

Rodent Damage Taking Over Your HVAC? Learn How to Fight Back

The sounds of squeaking and the scurrying of tiny feet in the hollows of your Marietta home might send you to the highest countertop in your kitchen. Evidence of rodent damage, however, can be both heard and seen - perhaps even in your HVAC system.

How and Why Rodent Infestations Occur

Rodents are often drawn specifically to the heating system in order to find a place of refuge from the cold. For that same reason, rodents like to nest in ductwork. They will chew on whatever they can find. When they begin to feast on HVAC electrical wiring, your home’s safety is compromised. Chewing through a wire can lead to an electrical fire and a damaged HVAC system. When rodents find their way into your ductwork and make nests or leave droppings behind, tiny fecal spores are swept along by the force of heated and cooled air moving through the ducts. These spores make their way into your home and contaminate the air quality.


The best way to prevent rodents from getting into your HVAC system and ductwork is to prevent them from coming into the home in the first place. Here’s what you can do:

  • Check the home’s exterior shell, and make sure it’s tightly sealed. A small rodent can enter through the smallest of cracks, even one smaller than a quarter. Use caulk and expanding foam spray to fill any holes and cracks that you find.
  • Make sure the registers to your ductwork are sealed with an impenetrable mesh to allow airflow but prevent rodents from gaining access to the system.
  • Check the attic and make sure there’s flashing around the perimeter to prevent rodents from entering through holes in the roof.
  • Check the condition of the outdoor part of the air-conditioning unit, looking at the casing for signs that rodents have penetrated it or have chewed on the wiring.
  • Limit access to water. Sometimes rodents in search of water are drawn into the home. Take care of any water sources that rodents might access, such as moist areas in the basement.
  • Set traps. Attract any rodents that are roaming around your home by setting humane traps in strategic areas.


Depending on how long the rodent damage has gone on, the cost to repair the damage can vary. Eventually, the damage to your system will likely cause it to malfunction, and you’ll need to call a repair contractor. If you schedule annual service, your service professional will identify rodent activity early on.

If you need help with preventing rodent damage, or you need to address HVAC system repairs because of it, contact Casteel Heating, Cooling and Plumbing. We’re happy to help our Marietta neighbors with HVAC maintenance, repair and replacement.