My Central AC Is Making a Roaring Noise

Fan System

• Your AC has a fan system that propels air through your duct work. A roaring noise is often an indication that the fan system is not functioning properly. The fan may have collected dirt or become damage. The motor that the fan uses is also a common source of roaring noises if it is beginning to burn out or showing signs of serious wear.

Ductwork

• The ductwork itself may also be a source of roaring noises when you use your central air. Ductwork can rattle and vibrate if it is loose. When it echoes through the ducts into your house, this can sound like a roaring noise coming from the AC unit itself. Check to ensure the roaring is coming from the system and not loosened ductwork or airflow problems in the ducts.

Unit Bolts

• If the roaring is coming from any part of your AC unit, including the compressor and evaporator, it is a good sign that components have become loosened. If bolts begin to fail, components will start to vibrate together when the AC is turned on, producing the roaring noise. Fortunately, finding loosened bolts and tightening or replacing them often turns out to be an easy fix.

Compressors

• The compressor is the component that compressors the refrigerant to help it absorb heat from the air before releasing that heat through evaporation. Compressors can sometimes make loud squealing or roaring noises. If your compressor has always made this noise, it may be a normal part of your air conditioner function and not a sign of any new damage. But if the noise suddenly increases or starts, it can be a sign that the compressor has developed leaks or cracks, a dangerous condition that should be quickly repaired.