Beyer Boys Logo

Heat Pumps Noises

Heat Pumps NoisesYou expect to hear certain normal noises when your heat pump is starting up, running, or shutting down, such as low-key whooshing, clicking, humming or squeaking sounds. However, loud noises that develop may be warning signs of potentially-serious problems, so it’s wise to have your HVAC pro investigate if you hear any of these concerning sounds:

Metallic Banging

A fan blade hitting against other internal components can produce a loud metal-on-metal banging noise. If this is occurring, shut off the system to minimize any damage and call for help.


Loose hardware, piping, ductwork, and other components that vibrate during normal operation can create an irritating rattling sound that gets louder over time. You can check for and tighten any loose cabinet screws, but if that doesn’t help, get a professional opinion on what’s causing the noise.

Gurgling or Hissing

A low refrigerant charge can produce odd gurgling sounds from your HVAC system. If you also hear a hissing sound coming from the equipment, it’s a clear sign of a refrigerant leak. A loss of refrigerant can result in energy waste and costly component damage, so these sounds should looked into promptly by an experienced technician.


Heat pumps can make a normal humming sound when they’re in defrost mode. However, if your unit is buzzing loudly and won’t cycle on, your HVAC pro needs to check for electrical component issues, such as a stuck relay switch, faulty capacitor, or failed motor.

High-pitched Shrieking

If your heat pump starts making a high-pitched shrieking noise, shut down the system and contact your HVAC contractor right away, because you may have a bad compressor and dangerously high refrigerant pressure within the system. Other possible culprits are a frayed or misaligned blower fan belt, or bad motor bearings.


Grinding noises are typically caused by dirt buildup or a lack of sufficient lubrication on a heat pump’s motors or other moving parts. The best remedy is regular preventive care that includes cleaning and lubricating key HVAC components.

For help addressing heat pump noises in your San Antonio-area home, contact us at Beyer Boys.

Our goal is to help educate our customers in the greater San Antonio, Texas area about energy and home comfort issues (specific to HVAC systems).