Troubleshooting Heat Pump Noise: Problems, Causes, and Solutions

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Heat pump noise problems such as buzzing, grinding, clicking, loud, gurgling, rattling, high-pitch, thumping, rumbling, hissing, whooshing, banging, humming, and howling are just some of the sound problems that will be covered here and explained, including the reasons for easy troubleshooting.

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During the normal air-to-air heat pump operation, either cooling or heating, it is normal to hear a soothing, humming, or purring sound.

Anything unusual, especially abnormal noise during operation, should be the first sign of problems and would require a professional to diagnose the problem.

Troubleshooting heat pump noise problems

Why is my heat pump making noise?

There could be several reasons why your heat pump is making a noise. Here are some of the most common causes:

  • Dirty or clogged air filter: If your heat pump is making a whistling or hissing noise, it could be due to a dirty or clogged air filter. This can cause your heat pump to work harder and make more noise than usual.
  • Loose parts: A rattling or clanging noise could indicate that some parts of your heat pump are loose or need to be tightened. Check the screws, bolts, and other fasteners to make sure they are all securely in place.
  • Refrigerant leaks: If you hear a hissing or gurgling sound, it could be a sign of a refrigerant leak. This can be dangerous and may require professional attention.
  • Fan problems: If the fan blades are damaged or unbalanced, your heat pump may make a grinding or scraping noise.
  • Motor problems: If the motor is malfunctioning or failing, it may make a buzzing or humming noise.
  • Dirty condenser coil: If the condenser coil in your heat pump is dirty, it can cause the system to work harder and make more noise.
  • Faulty reversing valve: The reversing valve in your heat pump is responsible for switching between heating and cooling modes. If it is damaged or stuck, it could cause a loud noise.
  • Compressor problems: A damaged or failing compressor can also cause a loud noise. This could be due to a broken piston or valve, worn-out bearings, or an electrical issue.

Whoosh sound

During the wintertime, when the outside temperatures are very low (freezing), and ice starts to build up on the outdoor unit, the heat pump will automatically melt the ice or snow build-up utilizing the defrost cycle.

The result of this action is not only the fog or vapor rising but the specific “whoosh” sound, which is nothing unusual. During colder weather, the heat pump can operate at different speeds, producing a higher noise level than when it is warmer.

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Metal sound

This is usually related to the fan hitting something while spinning; ice, wire, or metal element. The problem should be immediately taken care of to avoid any damage to the fan blades.

Clicking sound

Clicking sound is also normal; it takes place when you turn the heat pump on for the first time after a long time of inactivity. If you hear it more often, the problem might be with the start capacitor, and when it breaks, the heat pump won’t run. The clicking sound can also be coming from the refrigerant control valve and other electric components.

Clanking noise

The clanking noise indicates that some of the elements inside the heat pump are loose and need to be checked and tightened. Investigate the moveable parts, such as the fan belt, which gets loose due to wear.

The changes in the noise level are normal, and as long as the noise doesn’t exceed the level defined in the specification sheet, there is nothing that can be troubleshot; it is not considered the problem.

Grinding noise

Grinding noise means that there is a problem with the compressor or fan motor, actually bearings. If the motor lacks lubrication or there is dirt inside, start looking for a new motor.

Buzzing noise

A buzzing sound could indicate an electrical issue within the heat pump. This could be caused by a loose wire, a malfunctioning contactor, or a failing capacitor.

Bubbling sound

A bubbling sound usually occurs when the outdoor air enters the drain hose, especially when the house or apartment is completely closed, and the wind is strong.

Hissing sound

A hissing sound is caused by the discharge of humidified or ventilated air.

Vibration is also normal but can be reduced by installing rubber isolation pads under the heat pump.


It's important to note that heat pumps can make some noise when they are operating normally.

If you are experiencing a loud noise coming from your heat pump, it is recommended that you turn off the unit and contact a professional HVAC technician to diagnose and repair the issue. Continuing to run a heat pump that is making a loud noise could lead to further damage and potentially costly repairs.

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