The answer to 'why is my air conditioner smells bad' is that there could be several common causes, including mold or mildew buildup, a dead animal in the ductwork, or a refrigerant leak. These issues can lead to unpleasant odors coming from your AC system.
Mold and mildew often grow in the condensate drain line or on the coils of the air conditioner. This can happen if the system isn't properly maintained and cleaned regularly. A dead animal, like a rodent, stuck in the ductwork can also create a foul smell. And a refrigerant leak can release a pungent odor as the gas escapes.