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HVAC

Why is my HVAC making a banging, squealing, or rattling noise?

HVAC sounds that aren't normal — banging, squealing, rattling — each point to different problems. Here's what each noise means.

Most common causes

  • 01Banging at startup: loose or broken part
  • 02Squealing: worn blower belt or dry motor bearings
  • 03Rattling: loose panels, debris in unit, or loose fasteners
  • 04Clicking that won't stop: failed relay or control board
  • 05Hissing: refrigerant leak or air duct leak

What to do right now

1
Turn off the system if banging is loud or metal-on-metal — continued operation can cause major damage
2
Check that all access panels are secured
3
Look for obvious debris at the outdoor condenser unit

When to call a professional

Call an HVAC technician for any noise that's new, persistent, or getting louder. Squealing and banging in particular indicate mechanical failure that worsens quickly.

Need a HVAC pro?

Novum's licensed crew shows up, diagnoses the problem, and fixes it — flat upfront quote, no surprises.

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What Novum does:

We identify the noise source — whether it's a failing motor, refrigerant leak, or loose component — and repair it before it causes secondary damage to the system.

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