Common Debris That Builds Up In Air Ducts

Over the years, it’s not uncommon for ducts to get filled with dust, lint, pet dander and other debris. These materials contaminate indoor air, and they can exacerbate respiratory conditions like allergies and asthma.

Generally, you should clean your ducts every three to five years. However, there are some things that can indicate a duct cleaning is needed sooner.


When people cook and eat in the same room where they use their air conditioning, they drop food particles that can build up in the home’s air ventilation system. These crumbs, along with dust, can be blown through the vents with each cool or warm breeze. This debris can trigger allergies and aggravate respiratory conditions. A professional cleaning can remove these particles from ductwork.

Soot is another common allergen that can be found in ducts. It can settle in the winter during furnace use and resurface in the summer during AC run-off. This black dust can be a respiratory health risk and damage the efficiency of the AC.

It’s common for ducts to collect dust, dirt and pet dander as well. These contaminants are small and light, so the air drafts that blow through the ductwork carry them along. Even if you keep your house tidy, it’s likely that these contaminates will find their way into the ducts.

The air ducts can also harbor biological contaminants like rodents, insects and mold. If these pests make their homes in your ducts, they can circulate contaminated air throughout the entire home. In many cases, a combination of duct repair and cleaning is the best solution for this type of problem. The repairs will ensure that the moisture and biological contaminant isn’t carried through the ventilation system to other areas of the house.


Air ducts maintain circulation by transporting warm and cool air throughout your home. They also provide pathways for dust and other debris to escape and settle in rooms. Over time, this can cause a build-up of contaminants that negatively affect your indoor environment. Dirt is one of the most common contaminants that can build up in ducts. It can come from fabric items in your home, such as drapes and carpeting, or it may blow into the duct system from outside. Despite cleaning your home regularly, it is likely that dirt will accumulate in the air ducts over time.

A dirty air filter is not the only source of dirt in your ducts; it can also be caused by construction materials, such as bits of drywall and asbestos. These materials can be released into the air by contractors working in your home, or they could fall from deteriorating parts of your HVAC system.

Some service providers offer duct sanitizing with chemical biocides, which are designed to kill microorganisms. However, these products have not been fully tested for safety in ductwork and can be dangerous to your family’s health if not properly applied and monitored. Further, they cannot prevent future contamination and may encourage microbial growth. Biological contamination can be prevented by controlling moisture and correcting leaks in ductwork.

Animal Debris

Although we all love cute furry animals, you don’t want them making their homes in your ducts. Rodents are notorious for getting into ductwork through loose seals and cracks, where they build nests and leave behind feces. These fecal particles are circulated through your home, irritating allergy sufferers and others who need healthy indoor air quality.

These fecal particles can also lead to mold and mildew growth, which are a serious health risk. Mold spores release toxic chemicals that can cause headaches, fatigue, nausea, and other ailments in humans.

Another problem with animal debris is that it can be flammable. Dead rodents, birds, and other animals can catch fire in your ductwork, which could result in a devastating house fire.

In addition, animals can also introduce other allergens to your indoor air, such as pet dander and pollen. These contaminants are circulated throughout your home by the air conditioning system, which can aggravate allergy and asthma symptoms in household members.


Mold is a fungal substance that grows in moist environments. It can cause allergies in humans and pets. It can also damage surfaces it grows on. Molds get their nourishment from organic materials and other living organisms, such as dead leaves, plants and animals. They can also break down wood in buildings and food. They release enzymes that aid in this process. Molds can be toxic to people, especially when they are exposed in high doses. They can cause rashes, watery eyes and a sore throat. Mold spores can grow in air ducts and then be blown around the house by the AC vents.

If a homeowner notices that the AC vents have mold in or around them, they need to take action immediately. They should contact a professional air duct cleaning service to handle the mold removal and cleaning.

Air ducts are a great place for mold to grow because they have warm temperatures and lots of moisture. Mold needs to have these two things in order to grow. It doesn’t grow in freezing temperatures, but it will grow in warmer areas. It can live off of organic debris, such as dust, oil films, skin cells and dirt that is deposited on the surface of a material. It can also grow on surfaces like drywall, wallpaper, carpet and fabric.