HVAC System Sounds You Don’t Want to Hear

Your HVAC system contains electronic and mechanical components that make different noises. You expect to hear normal sounds when your HVAC unit is operating normally. However, loud and rumbling noises can be indicative of a bigger problem. Be sure to schedule an appointment with your local HVAC professional to prevent further damage to your system.

Here are 5 sounds that should never be coming from your HVAC system.

Repeated clicking sounds

Clicking sounds can be heard when the HVAC unit is turned on or off. But if you hear repeated clicking sounds coming from the outside compressor or control panel while it’s operating, this can be indicative of an electrical signal problem.


Squeaking noises from either the outdoor or indoor unit may signify a lack of adequate lubrication of the motor bearings. To solve the problem, you just have to add the proper type of lubricant through the unit’s oil portal.

Screeching or squealing

It is normal to hear a high-pitched squealing sound on startup. However, if the sound continues during operation, it may be due to a worn or slipped fan belt. The belt should be replaced before it breaks. Otherwise, your blower will no longer turn. Turn your system off right away and have your technician address the issue promptly.

Banging or rattling

Rattling usually means that a component in the system has worked loose – either the motor, blower assembly or other hardware. The loose part may fly off and seriously damage nearby components if not located and secured.

Shut the system off if you hear loud banging noise. It is best to contact an HVAC technician to have the part secured back into place before it comes off or damages other components.

Hissing or screaming

A loud hissing or screaming noise coming from the compressor, evaporator or coolant lines could be a sign of a refrigerant leak. Immediate action is needed because refrigerants can be dangerous to humans. Don’t waste any time. Shut down the unit call for professional help right away.

Erie, Firestone, Dacono, Lafayette, Broomfield, Thornton, Colorado

Need HVAC Service?

Contact the experts at Carbon Valley Heating & Air.

Call us at 303-833-4466!