The answer to 'why is my mini split smells bad' is that there are a few common causes for this issue, including mold or mildew buildup, a dirty air filter, or a refrigerant leak. A musty or foul odor coming from your mini split system can be a sign of a more serious problem that requires professional attention.
One of the most common causes is mold or mildew growth within the indoor unit or ductwork. This can happen when moisture builds up due to poor drainage or lack of maintenance. Another potential issue is a dirty air filter, which can restrict airflow and allow bacteria and odors to accumulate. Lastly, a refrigerant leak can cause a pungent, chemical-like smell as the refrigerant escapes.