AC Smells Like Vinegar Or Rotten Eggs
A sharp vinegar or rotten-egg (sulfur) smell from the vents. Usually mold/bacteria buildup, a clogged drain, or moisture problems in the AC system.
Find a TechnicianCommon causes
- Bacterial/mold growth on the evaporator
- Clogged AC condensate drain
- Old cabin air filter
- Standing water in the ductwork
- Rarely, an electrical or battery odor pulled into the intake
Frequently asked questions
Is a rotten-egg smell dangerous?
From the AC it's usually mold/bacteria, not harmful gas. A persistent sulfur smell elsewhere (like exhaust) should be checked separately.
Will an air freshener fix it?
No — that only masks it. The source (mold, drain, filter) needs cleaning or replacement to remove the smell.
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