The answer to 'why is my air duct filthy' is that air ducts can become dirty and clogged over time due to a buildup of dust, debris, and even mold. Common causes include poor indoor air quality, lack of regular cleaning, and issues with the HVAC system. Symptoms may include reduced airflow, musty odors, and visible dust or debris in the vents.
To address a filthy air duct, you'll first want to inspect the system and identify the root cause. Simple DIY cleaning like vacuuming or wiping down visible areas may help, but for more extensive buildup or inaccessible areas, it's best to call in a professional air duct cleaning service. They have the right equipment and expertise to thoroughly clean the entire ductwork system and ensure proper airflow and indoor air quality.