Why Is My AC Making Buzzing Noise? Common Causes and Fixes

An HVAC technician servicing an outdoor air conditioning unit with professional repair tools during a residential heating and cooling maintenance visit.

The air conditioner turns on normally, cool air starts moving through the vents, and then the buzzing starts. The sound is steady, distracting, and impossible to ignore once it begins. It does not sound like the normal low hum most AC systems make during operation. Instead, it sounds electrical, mechanical, or strained, which immediately raises […]