It's unnerving to hear a hissing noise coming from your air conditioner. When your AC makes odd noises, you don't know if the problem is minor or a sign of a serious problem with your equipment. That's why you should call an air conditioning repair service when you hear any kind of unusual noises coming from your AC equipment, including hissing. Here are possible reasons for a hissing sound.
1. The Compressor Is Malfunctioning