The answer to 'why is my air duct buildup' is that air ducts can accumulate dust, dirt, and other debris over time, leading to a buildup that can reduce airflow and indoor air quality. Common causes include lack of regular cleaning, pets, smoking, and construction work in the home.
Symptoms of air duct buildup may include reduced airflow, increased dust and allergens, and higher energy bills as the HVAC system works harder. Solutions include regular professional duct cleaning every 3-5 years, as well as simple DIY steps like changing air filters and sealing any duct leaks.