The answer to 'why is my air duct odor' is that there are several common causes for air duct odors, including mold growth, pest infestations, and accumulated dust and debris. These issues can lead to musty, unpleasant smells circulating throughout your home. Symptoms may include a persistent odor, poor indoor air quality, and increased allergy or respiratory symptoms.
To address air duct odors, start by inspecting the ducts for any visible signs of mold or pests. You may be able to clean and disinfect the ducts yourself, but for more severe issues or if you're unsure of the cause, it's best to call in a professional HVAC cleaning service. They have the specialized equipment and expertise to thoroughly clean and sanitize your ductwork to eliminate odors.