What's That Noise? Decoding HVAC Sounds

Normal Sounds

Gentle humming from the outdoor unit is normal operation. Soft clicking at startup and shutdown is typical. Whooshing air through vents should be steady and not loud.

Concerning Sounds

Banging or Popping

From ducts: Often just thermal expansion as metal heats or cools. Usually harmless but sometimes fixable with duct modifications.

From furnace: Could indicate delayed ignition, where gas builds up before lighting. This is a safety concern - call a technician.

Squealing or Screeching

Usually indicates belt or bearing issues in the blower motor. Turn off the system and call for service to prevent further damage.

Grinding

Metal-on-metal grinding suggests serious motor problems. Turn off the system immediately and call for repair.

Rattling

Often a loose panel, screw, or component. Check for anything obvious, but persistent rattling may need professional diagnosis.

Buzzing

Could be a failing capacitor, relay, or electrical connection. Electrical issues should always be addressed by a professional.

When to Call Immediately

Don't Ignore Unusual Noises

Catching problems early prevents more expensive repairs. If something sounds wrong, contact us for diagnosis.