Mice, insects or pet hair in your air ducts: what to do

Updated November 10, 2026 · KeystoneProGuide editorial team

What should you do about rodents or insects in your air ducts?

Get the animals out first, safely, and then have the ducts cleaned. An infestation of vermin, meaning rodents or insects, is one of the three conditions in which the U.S. Environmental Protection Agency (EPA) says you should consider having your ducts cleaned.

Pet hair is a different matter and is covered further down. It is not on the EPA's list.

Why does the exterminator come before the duct cleaner?

Because the EPA says that whichever condition you have, the underlying cause must be corrected before cleaning, or the problem will likely recur. Cleaning ducts that mice can still get into means cleaning them again.

The Centers for Disease Control and Prevention (CDC) is specific about who to call. Where there is evidence that rodents have got into heating and cooling ventilation systems, it says to contact a professional rodent exterminating service to remove them. It adds that companies specializing in duct cleaning are familiar with the problems and risks of rodent infestation in ventilation systems.

Pennsylvania's Department of Agriculture says anyone using pesticides on another person's property needs a commercial applicator license and must work for a company that holds a pesticide business license. That is a fair thing to ask an exterminator about.

Why should you not vacuum up droppings yourself?

The CDC says not to vacuum or sweep rodent urine, droppings or nesting materials. Doing so can put tiny droplets containing viruses into the air, and diseases are mainly spread from rodents to people when contaminated air is breathed in.

For droppings on hard surfaces in the house, the CDC's method is to put on rubber or plastic gloves, spray the droppings with a bleach solution or an EPA-registered disinfectant until very wet, let it soak for five minutes or as the label directs, and wipe up with paper towels.

Inside a duct system that method does not transfer. You cannot reach most of the ductwork, and the EPA says moisture should not be present in ducts. For ventilation systems the CDC points to professionals instead. The EPA also notes that a duct system can distribute contaminants throughout a home.

What are the signs of vermin in ducts?

The sources describe the evidence in general terms: droppings, urine, nesting materials and dead rodents, in the CDC's list, and rodents or insects in the ducts themselves, in the EPA's. Around a duct system, the places a homeowner can look without disturbing anything are the registers, the return grille, the filter and the area around the indoor unit.

Ask any company that reports an infestation to show you what it found. The EPA says to do that for every kind of contamination.

What does it cost?

Removal and cleaning are priced separately. Published figures for the pest side:

Angi and Fixr: $200 to $1,200 for pest removal. Angi explains that the low end reflects a pest control treatment and the high end full rodent removal.
HomeAdvisor: $200 to $1,200 for rat extermination, in addition to the cleaning.
Forbes Home: $200 to $900 for rodent control.
HomeGuide: $150 to $600 for rodent removal.

HomeAdvisor's advice on the order of work matches the EPA's: hire an exterminator before the ducts are cleaned. The cleaning itself, on the EPA's figure, typically runs $450 to $1,000 per heating and cooling system.

Will a sanitizer be needed afterwards?

One will probably be offered. The EPA's position on biocides in ducts applies here as it does to mold. The product must be registered for the use, none is registered for fiberglass duct board or fiberglass-lined ducts, and it should go on only after the system has been cleaned of visible debris. Sanitizers, ozone and sealants sets out the questions to ask.

Soiled insulation is a separate issue. The CDC says exposed insulation contaminated with rodent urine and droppings should be bagged for removal. If your ducts are lined or wrapped with insulation that rodents have fouled, ask whether the company proposes to replace it, and get that priced as its own line.

Does pet hair mean your ducts need cleaning?

Not according to the EPA. Its three conditions are substantial visible mold, vermin, and ducts clogged with excessive dust and debris or blowing particles into rooms. Pets do not appear on the list.

NADCA, the duct cleaners' trade association, does count pets. It lists pets that shed a lot of hair and dander among the things that may lead a household to clean more often. That is the trade body's view. The EPA's test is what you can see in the ducts. If hair has built up into deposits heavy enough to clog a duct, the third condition applies. If there is a light layer, the EPA says that is normal.

For people who are allergic, the EPA's asthma guidance explains what triggers symptoms: proteins in a pet's skin flakes, urine, saliva and hair. Its list of actions is about where the pet goes and what you clean.

Keep the pet out of the bedroom of the person with asthma, and off the furniture.
Use an air cleaner with a HEPA filter.
Vacuum carpets and furniture when the person with asthma is not around.

Duct cleaning is not on that list. Does air duct cleaning help with allergies? goes further into the evidence.

What keeps hair and dust out of the system?

The filter. ENERGY STAR says to inspect, clean or change it once a month. The EPA says to use the highest efficiency filter the system's manufacturer recommends, to change it more often if it clogs, and to make sure air cannot bypass it through gaps around the holder.

The EPA also says return registers get dusty in normal use, and can be vacuumed or removed and cleaned.

What should you do once the animals are gone?

Have the entry points closed, then look at the ducts. The EPA's order is cause first, cleaning second, and its advice on choosing a company applies as usual: talk to at least three, get written estimates, and ask each to show you the contamination.

Signs your air ducts need cleaning explains how to check for yourself, and businesses that clean ducts are listed on the air duct cleaning directory page.

Sources

Should You Have the Air Ducts in Your Home Cleaned?, U.S. Environmental Protection Agency
How to Clean Up After Rodents, Centers for Disease Control and Prevention
Asthma Triggers: Gain Control, U.S. Environmental Protection Agency
Maintenance Checklist, ENERGY STAR (U.S. Environmental Protection Agency)
FAQs, National Air Duct Cleaners Association (NADCA)
Pesticide Applicators, Registered Technicians, and Certification Exams, Pennsylvania Department of Agriculture
How Much Does Air Duct Cleaning Cost? [2026 Data], Angi
How Much Does Air Duct Cleaning Cost in 2026?, HomeAdvisor
How Much Does Air Duct Cleaning Cost? [2026 Data], Fixr
How Much Does It Cost To Clean Air Ducts?, Forbes Home
How much does air duct cleaning cost?, HomeGuide