You know the importance of seasonal HVAC maintenance. But most of these cleaning and repair efforts focus on your heating and cooling units themselves rather than the system of ducts that delivers heated or cooled air throughout your home.

When your ducts become obstructed, dirty, or compromised, the issue can harm your indoor air quality and decrease the overall efficiency of your HVAC system. The obvious answer to these problems is professional duct cleaning, but when do you need to schedule a cleaning?

In this blog, we list six signs that your ducts need cleaning sooner rather than later.

1. Decreased Airflow Through a Vent

Obstructions in your ducts can prevent air from flowing as it should. While your system is running, open all your vents and observe how much air you can feel coming from each one.

If one vent releases significantly less air, its connected duct likely needs cleaning.

2. Dust or Debris in the Air by the Vents

When you turn on your HVAC system, do you see a puff of dust come out of the vents? If you can see dirt, dust, or other debris floating in the air coming out of your vents, your ducts are probably full of the same contaminants.

Without a thorough duct cleaning, your HVAC system circulates these foreign particles in your home, reducing your indoor air quality.

3. Mold or Slime Growth

Because ductwork is dark and often warm inside, unwanted organic growth can take hold on the interior surfaces. This growth includes mold species that can be toxic, and all organic growth in your ducts creates particles that contaminate your air.

To look for signs of mold, take off your vent covers and look into the ducts. Any slime or plant matter present should be tested by a mold specialist. If you notice visible moisture in the duct or around the opening, have the system inspected to reduce the risk of mold growth.

4. Pest Infestations in the Ductwork

Many pests, such as rodents, thrive in the same environmental conditions as mold. If you notice scratching noises in your ductwork or rodent droppings or dead insects around your vents, have a pest control expert check for an infestation.

To eliminate these pests, you may need to have an exterminator spray or fumigate in addition to having your ducts cleaned.

5. Pet Fur Trapped in Vent Grills

Loose pet fur is one of the most common types of debris that blocks ducts. Pet hair often clumps together with other debris to create larger obstructions. If you have a pet or pets, keep an eye out for any fur in or around vent covers.

If you have a long-haired animal, a large pet, or multiple furry pets, consider scheduling routine cleanings to keep your ducts clear.

6. Unpleasant Odors That Originate From Your System

While most of the debris in your ducts is odorless, such as dust particles, other contaminants can create unpleasant smells when you use your HVAC system. Common causes of abnormal odors include rodent droppings, wet pet hair, organic growth, and stagnant water.

When you schedule the cleaning, try to describe the smell to the HVAC professional since certain odors can indicate complex duct issues such as mold growth. These risks usually must be handled before your ducts can be cleaned.



If you notice any combination of the signs listed above, have an HVAC technician evaluate your system. In most cases, a professional duct cleaning should address most or all of these issues.

To learn more about the benefits of air duct cleaning, visit the All American Air & Electric, Inc. duct cleaning page.