Heating & Cooling

5 Reasons Your Heat Pump is Making a Clicking Noise

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It is easy to identify if your heat pump is operating normally by the noise it is producing. When it is running normally, it produces a soothing sound or noise. During heat exchange, the compressor adds to the sound of the fan in your heat pump.

Heat pumps typically produce a clicking noise after being inactive for an extended period or when first turning on. Most soft clicking noises are entirely normal when you start and stop your heat pump. If the clicking noise persists, it could indicate a fan, compressor, or thermostat problem.

It’s really a struggle when your heat pump starts to make clicking noises. However, it may not be as severe as it seems. This article will help you identify why your heat pump makes that clicking noise and what you can do to fix it.

What Does It Mean When Your Heat Pump Makes a Clicking Noise?

A clicking sound is puzzling, especially coming from your heat pump unit. A clicking heat pump can imply that a part of your heat pump is loose and may be hitting another part of your unit. It could also mean that the fan may be brushing against something affecting its regular motion.

A clicking sound is concerning as it may indicate an issue with your unit’s electrical connection. If the unit only clicks once or twice when turned on, it is considered normal. Repeated clicking is, however, alarming.

An issue with the control panel may be another reason why your heat pump unit produces a clicking noise. There are likely faulty electrical signals that make the clicking noises accompanied by electricity sparks causing the switches to turn either on or off. 

If you notice that the heat pump is producing a clicking noise accompanied by sparks of electricity, turn your unit off and seek assistance from experts to assess your unit.

What Causes a Heat Pump to Make a Clicking Noise?

The clicking heat pump noise is in most cases caused by a fan obstruction. When the unit becomes warmer, the clicking sounds may increase, which could be caused by the fan blades hitting a component in the unit. 

1. A Loose Fan or Fan Problems

Your heat pump fan is likely loose, which causes a clicking sound. It happens if you turn the heat pump on or off. Wear or tear and lack of maintenance are the main issues that may affect the fan. 

These issues likely affect the fan, which may hit the condenser. When the fan moves up and down, the movement causes a recurring clicking sound. 

An obstruction such as a stick or debris can prevent the heat pump fan from spinning freely. In some other situations, the fan blade may bend. The fan may need to be replaced by an expert in such a case.

2. Control Board and Capacitor Malfunction

The clicking sound may occur if the unit has trouble turning on in some cases. This indicates various components in your unit may have experienced a malfunction, such as the control board, the capacitor, or the motor. 

If your unit produces a clicking sound and not turning on, it is wise to seek professional help. Solving this on your own can lead to more damage to your unit.

3. The Thermostat

You may be dealing with a malfunctioned thermostat if the clicking sound persists once you turn on the AC. Like any other component, thermostats have a shelf life. Using your unit over a long period may result in loose wires, which may interfere with the normal working of the heat pump system.

The thermostat may be sending mixed signals to the capacitor; however, it is impossible to execute them since the wires are shorted. 

It may also happen that the capacitor control switch is faulty. In this case, the best decision is to seek professional help from a technician to do the required repair. 

4. Compressor Hardware Problem

It is not often that you find the clicking sound originating from outside the unit. Although this is rare, the compressor may cause it to happen. It may also occur as a result of loose bolts.

A flexible refrigerant tubing can be another reason your unit makes a clicking sound from the outside. From time to time, the refrigerant tubing may hit the frame of the AC, producing an irritating clicking noise. The clicking sound may also be a result of the refrigerant line. 

A practical solution may be tightening the bolts of your unit and removing any material or debris in the system. A technician expert must look through the system to avoid further damage.

5. Icing the Unit

Icing the unit is another common reason your heat pump may produce a clicking noise. The clicking noise may sound more like a cracking or a popping sound in such a case.

The icing of your heat pump unit happens in the case where the temperatures are set too low. Many ACs have inbuilt sensors that detect ice formation. 

When ice forms, the sensor turns off to allow the ice to thaw. The unit’s drainage system then directs the melted ice outside the device and discards it.

When the drainage system is faulty, the unit cannot eliminate ice that forms during very low temperatures. You are bound to hear a cracking and clicking noise as the ice moves within the unit. It is essential always to check the drainage system of your unit.

What Does a Bad Heat Pump Compressor Sound Like?

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Bad heat pump compressor sounds include rattling and vibrations, clanking sounds, popping sounds grinding, hissing, and squealing noises. If you start to hear noises from your heat pump compressor, the pump compressor likely needs to be repaired or assessed by an expert.

  • Whooshing Sound – Heat pumps may make a whooshing sound, particularly when on defrost mode. In this mode, the valve shifting leads to the swooshing noise. The sound may be louder during winter when the heat pump is used the most. 
  • Metal Sound – During extremely low temperatures, fan blades are likely to produce a metal-like sound that hits the chunks of ice. It may also be from blades hitting loose wires and other essential components in your unit. If you hear such noise, it is important to immediately turn your unit off to avoid further damage to the heat pump components and the fan blades. Turning off your unit also reduces the amount of work done by the motor.
  • Rattling and Vibrations – This kind of sound indicates that the hardware components of your unit are loose and need to be adjusted. You are also likely to hear this sound if the piping of the refrigerant is tightly strapped. This rattling sound is likely to worsen over time if left unfixed.
  • Clanking Sound – Loose fan belts often produce a clanking sound. An expert technician may solve this issue by tightening the fan belts of your heat pump. 
  • Popping Sound – This sound usually occurs in the process of the compressor receiving the liquid refrigerant. There may be an issue with the compressor that needs further attention.
  • Gurgles – A gurgling sound is a result of the low refrigerant level in your unit’s compressor.
  • Grinding Noise – This noise may be due to dirty components or debris on your heat pump compressor or the need to add lubrication to your system.
  • Shrieking Noise – These are unbearing loud noises that indicate that the heat pump’s compressor is faulty. When you hear this noise, it is essential to shut down the system immediately. Dirty motor bearings can also produce a large shrieking noise, thus need for replacement.
  • Hissing Sound – A hissing sound is an indication that there is a refrigerant leak in the system, thus needing repair by a professional.
  • Squealing Noise – A squealing sound is an indicator that the heat pump motor is bad and needs repair. 

Troubleshooting Bothersome Heat Pump Noises

It is possible to troubleshoot some bothersome heat pump noises on your own. There are problems that you can troubleshoot yourself before seeking professional help. 

Below is a description of heat pump noises that you can troubleshoot at the comfort of your home.

Whistling Noise

A whistling sound may result from air gushing quickly through the unit’s opening. It is usually a result of the accumulation of dust, debris, or any other obstructing material on your unit. This issue is relatively easy to solve. A simple cleaning can do the trick.

Rattling Noise in the Air Duct System

A rattling sound in your unit indicates debris accumulation in the system’s fan. Before taking out the debris, it is essential to shut down the system and remove the debris from the fan blades. 

It may be challenging to clean debris out of the air ducts, mainly because locating it may be challenging. A good start is pinpointing where the rattling noise is coming from and removing the air duct debris. If you’re unsuccessful, you may seek help from an expert technician. 

Metal Sound

You can reduce the metal noise by tightening any loose screws and nuts which may become loose during operation. The problem may also be a bent fan blade. You may solve this by attempting to straighten the blade. If this does not work, you may also buy a new fan to replace the broken one. 

Vibration Sound

An expert with little technical expertise can solve vibrations in your system. You can try to locate the loose equipment in your unit causing the vibrating sound. Tighten the screws and nuts to secure everything in place.

Loud Humming

You typically need to replace electrical components that produce a loud humming sound. A humming sound is typical, but a part is either worn out or damaged if it becomes too noisy.

It is possible to replace the electrical component by yourself. However, you may choose to seek assistance from a technical expert. 

Hissing Sound

A hissing sound may prove challenging to troubleshoot. However, if you know more about refrigeration systems, you may fix this problem.

Loud Shrieking Noise

Loud shrieking noise only indicates that the problem is your heat pump fan motor. To solve this challenge, you will have to replace the motor. 

The following summarizes how to solve the problem of noisy heat pumps:

  • Tightening screws and bolts
  • Cleaning the fan blades
  • Use absorption pads
  • Replace malfunctioned components
  • Unclog the drains
  • Remove debris or obstructing materials

What Does a Good Heat Pump Compressor Sound Like?

Your heat pump may normally operate in some cases even though it produces some noise. Startup and shutdown sounds, gentle buzzing, and fan motor noise are considered normal compressor sounds. It is essential to familiarize yourself with the noises your heat pump makes when it’s running normally. 

Familiarizing yourself with the typical noises of your heat pump allows you to detect unusual sounds coming from your unit. Heat pumps are devices with moving elements such as fans and motors, capable of producing noise during operation.

Below is a description of usual heat pump noises that indicate a well-operating heat pump. 

Startup and Shutdown Sounds

Many people do not realize that heat pumps make shutdown noises. It may be because the pump is working away from the office or home where the noises cannot disturb you.

Most compressor units may produce a loud sound similar to a washing machine when first turned on. This noise should last only for a couple of minutes. Similarly, when the unit shuts down, some noise is produced. 

Defrost Mode

A byproduct created during the operation of your unit system is excess cooled air that accumulates outside the heat pump compressor unit. It is only a matter of time until your heat pump evaporator unit starts to freeze. 

When the evaporator unit freezes, the unit becomes less efficient and may prove difficult in transferring heat. When this happens, the sensor in your unit’s system senses this buildup and automatically shifts to defrost mode for some minutes. You may hear a swooshing sound when the unit switches to defrost mode. 

Gentle Buzzing

If your heat pump compressor unit produces a humming noise, the unit is operating normally. Electrical components in your unit, such as coils and contactors, make a humming sound during regular operation.

Fan Motor Noise

Air plays a crucial role in transferring heat in and out of your office or home. Air movement is made possible by using a large fan present at the top of the heat pump. Fans tend to create a little noise when running; however, this may not bother you. 

The noise produced by the fan should be smooth and not loud. It should also be a consistent sound throughout the unit’s running time. It is also possible to hear a clicking noise when you start the fan. This noise should also not be alarming.

Heat pumps should generally produce noise levels between 17dB and 26dB. Some large units may make more noise as these units heat big spaces. These units have a rating between 40dB and 60dB.  

Traditional heat pump units are not as quiet as modern units. Therefore, the age of your unit can be a contributing factor to the noise produced by the system. 

What To Do If You Notice Noise Coming From Your Heat Pump

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You may not be familiar with the working of your unit once it starts producing disturbing noise. If you have doubts, the first step should be to call a professional to look at your heat pump compressor unit.

An expert will ask you a series of questions about the unit. Some of these include:

  • The age of your unit
  • The type of noise it is making, for example, clicking, popping, banging
  • Location of the noise
  • Frequency of the noise
  • For how long has the noise been occurring?
  • When does the noise occur? Is it during start-up or when shutting down?
  • The refrigerant you use

It is vital to note that this issue may be difficult to diagnose over the phone. A heat pump unit has many moving parts; thus, it is essential to isolate the problem by inspecting it directly.

However, these questions are also important as the expert can reduce the time needed to identify the problem at hand. Essential questions such as the age of your system and the type of noise can help you know whether you may require a new system. 

A conditioner that is more than ten years old may be hard to repair due to the unavailability of spare parts, or the unit may be simply too old to repair.

An Ongoing Maintenance Plan

The best way to prevent unwanted noises from your unit is to have a maintenance routine or plan. Ensuring that your unit is always clean and away from wet surfaces is crucial. 

Ultimately, maintenance visits by a professional prevent any rising issues ensuring that your unit is running efficiently and smoothly. If you wait until your unit produces unwanted sounds, calling an expert may not be the right way to handle things. It is likely to cost you more for a problem you could have earlier prevented.


There are various reasons why your heat pump may be producing a clicking noise. In most cases, this should not be alarming. The unit may make a clicking noise once you turn it on after a long period of inactivity, which is considered normal.

If the noise persists, then there is a problem with the electrical components of your unit that need repair or replacement. Other parts in the unit, such as loose screws, damage to the thermostat, or damaged fan blades, contribute to a clicking sound.

Bad heat pump compressors make rattling, clanking, popping, grinding, and hissing sounds that indicate severe damage. To fix these noises, you typically need to have a professional assess and fix the problem with your heat pump.



Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.