We’ve all experienced it – turning on the AC for the first time in the season and being greeted by an unexpected, unpleasant smell. Don’t ignore it! Those odors are often a sign that something’s amiss with your HVAC system. Let’s break down some common AC smells and what they might indicate.

Common AC Smells and Their Causes:

Musty or Moldy Smell:
- Cause: This often indicates mold or mildew growth within your AC unit or ductwork. Moisture buildup, especially in humid climates, creates the perfect breeding ground.
- What to Do: A professional cleaning of your AC unit and ductwork is crucial. Address any sources of excess moisture.
Burning Smell:
- Cause: A burning smell can signal a variety of problems, including a burning motor, overheated wiring, or a dirty air filter.
- What to Do: Immediately turn off your AC and call an HVAC technician. A burning smell is a serious safety hazard.
Rotten Egg Smell:
- Cause: This is often a sign of a gas leak, which is extremely dangerous.
- What to Do: Evacuate your home immediately and call your gas company and an HVAC professional. Do not turn on any electrical switches or appliances.
Chemical Smell:
- Cause: A chemical smell can indicate a refrigerant leak. Refrigerant is a potentially harmful substance.
- What to Do: Turn off your AC and call an HVAC technician. Refrigerant leaks require professional repair.
Dirty Sock Smell:
- Cause: This is often caused by bacteria and mold growing on the evaporator coil.
- What to Do: A professional cleaning of the evaporator coil is necessary.