- Some types of mold produce poisonous substances called mycotoxins, which can cause a variety of health problems, including allergic reactions, breathing problems and nosebleeds, according to the Florida Department of Health. Toxic mold in an HVAC system can distribute spores throughout the home.
- Mold often appears either as fuzzy growth on a surface or through what the Florida Department of Health describes as a distinctive musty smell. Homeowners who smell mold in the air should inspect the air conditioner's evaporator coils, drains pan or ducts for water puddles or visible mold.
- To avoid risking further exposure to potentially toxic mold, homeowners should leave the task of mold remediation and removal in HVAC ducts to trained professionals, according to the U.S. Environmental Protection Agency. In many cases, ductwork overrun by mold requires replacement instead of cleaning.