The answer to 'air duct moldy' is that mold growth in air ducts is a common issue that can be caused by excess moisture, poor ventilation, or leaks. Symptoms include musty odors, visible mold, and potential health problems for occupants. The solution typically involves professional air duct cleaning to remove the mold, followed by addressing the root cause to prevent future growth.
While some minor mold issues can be addressed with DIY cleaning methods, it's generally recommended to call a professional air duct cleaning service for more extensive mold problems. Professionals have the right equipment and expertise to properly clean and disinfect the ducts, and they can also identify and fix the underlying moisture problem to prevent the mold from returning.