Noisy Heat Pump: How to Troubleshoot and Make It Quiet

Are you losing sleep or afraid to go outside because of a noisy heat pump? It squeals or grinds and scares the bejeebers out of you? It’s time to take action and reclaim some tranquility before your heat pump decides to quit.

How to Quiet a Noisy Heat Pump? The disruptive noise provides information about the problem. It may be solved through regular maintenance or a quick fix like:

  • Tighten mounting bolts
  • Install vibration absorbing pads
  • Clean the fan blades
  • Secure loose parts
  • Level the heat pump
  • Replace noisy parts
  • Unclog drains
  • Remove leaves and debris

In this article, you’ll learn about acceptable heat pump noise levels, what typical sound is, and what should raise red flags. You’ll discover some maintenance tips that can alleviate noise and some repairs that will fix others. By the end of the article, you’ll have a better understanding of where the disturbance is coming from. That way, if you’re comfortable around tools, you can fix it, or be more comfortable discussing it with a repair company.

Noisy Heat Pump

Heat Pump Noise Levels

A heat pump has an indoor component that should have a noise level between 17dB and 26dB. The outdoor heat pump unit does the bulk of the work, producing heat for the house in the winter, and cooling it during the summer. Heat pumps should be installed as far away from windows and neighbors as possible.

Many communities have noise regulations that also address heat pump sound. The closer the machine is to the property line or a neighbor’s window, the stricter enforcement. The standard acceptable noise level at the closest property line is less than 42 decibels (dB). If a unit is rated louder than 42dB, most jurisdictions require the granting of planning permission.

Most new heat pumps have a noise rating between 50 and 95 decibels. Larger units required to heat-cool bigger spaces, often produce more noise. Many quiet heat pumps have a rating between 40dB and 60dB.

For comparison, a vacuum cleaner is around 70dB, which is 4-times louder than 50dB and 8-times louder than 40dB. A pump that operates at 95dB, however, is 32-times louder than the 42dB limit. If a unit needs maintenance or repair, it can be significantly louder than it was when new.

Why Are Heat Pumps So Loud?

If you feel your heat pump is louder than it should be, check the owner’s manual for its sound rating. Purchase or borrow a sound meter, or upload a free sound meter app on your phone and check to see how much louder it is than rated.

There are many reasons a unit or compressor may be louder. Some may be addressed through regular maintenance; others may require a service specialist visit. Here are some common concerns and sounds:

Loose Parts – rattling, vibrating and buzzing

Unbalanced Fans – vibrating, rattle, metallic clipping or squeak

Heat Pump Is Not Leveled – vibrates at start-up and shut-down, tapping or clicking when operating, swoosh sound when defrosting

Problems with Refrigerant – gurgling, pinging, popping, buzzing, clanking or grinding when compressor working

Pump Motor Going Bad – groaning or screeching noise

Compressor – whining, hissing, or whistling

Electrical Issues – loud humming, clicking or snapping sound

Failing Valves or Solenoids – clicking or humming noise

Debris – clicking, rattling or whirring

Ice – rattle, clicking, vibration, or whoosh

Plugged Drain – wet or bubbling noises

Rodents and Birds – whirring or clicking 

Common Heat Pump Noises

A heat pump should be located away from windows, so it’s uncommon to hear much noise unless you’re near it outside. When it’s heating or cooling, it’s expected that the windows are closed, so the benefit of the appliance isn’t lost out the window.

Heat pumps, like a refrigerator or hot water tank, make noise during regular operation. Some noises are common and tell what cycle the pump is going through – start-up, shut-down, defrost, opening or closing valves, or the fan, to name a few. Each has a unique sound or two. During summer, the unit may make some different sounds than in winter, and be quieter too, due to the reversed cooling-heating process.

Normal Heat Pump Noises

The sounds the heat pump typically makes indicate what the pump is doing. The volume and duration of the sound shouldn’t fluctuate much from day to day operation, though, so if it does, there may be an issue brewing.

1. Noises During Start-up and Shut-Down

At start-up, the compressor may make a thumping similar to a washing machine with an unbalanced load. During shut-down, the compressor may make a tapping-clicking or pinging sound, similar to the sounds you hear from a cooling car engine. The noises should only last for a minute or two.

2. Heat Pump Defrost Cycle Noise

During the heating process, cool air is generated around the evaporator coils. Since it is cold outside, the coils can develop frost or ice build-up, making the unit less efficient. The heat pump senses this and automatically switches to defrost. The whooshing or swooshing sound that accompanies the switch to the defrost mode can seem loud and may last several minutes.

3. Fan Motor Noise

The movement of heat into or out of a building is assisted by a large fan located at the top or side of the appliance. The fan moves the large volume of air over the coils needed for the heat exchange process. The click of a relay switch may accompany the start and stop of the, and there should be a quiet and consistent rotational whir as the fan operates.

4. Rattling

A rattle or flutter is a common sound when some models start-up or shut-down. It should only be a cause for concern if it is an uncommon or unusually loud noise.

5. Clicking Noise

A clicking sound may also be heard when the appliance is starting or stopping. It could be relays and switches, or the ticking associated with the expansion or contraction of metal components.

6. Gentle Buzzing / Humming Noise Inside

Most large electrical appliances have a gentle humming or buzzing sound as electricity is transferred through components. During the various modes of operation, internal electrical relays, contactors, and coils are energized and make a quiet noise.

7. Squealing

Some heat pumps have a squeal when they start operation – it may be a quiet whistle or high-pitched. The sound should also last for only a minute or two (or less). If it’s not a common sound for your unit, then it indicates a problem developing.

Worrisome Noises

If you know the sounds your heat pump commonly makes, any abnormal noise should raise a flag. A noisy heat pump is a cause for concern as loud, and unusual sounds indicate a there is a problem. It is important to note, though, that some older models become louder as they age, and replacement is the only solution to their noise.

Loud Vibration

Loud vibrations or rattles commonly indicate that something has become loose, especially if the noise becomes louder with time. Locating where the sound originates and tightening loose parts should solve the problem. If the unit has always had a vibration, it could be caused by the refrigeration coils being strapped too tightly, preventing them from expanding normally.

Clanking

A worn or loose belt may cause a clanking. A loose part or debris interfering with a moving part can also cause a clanking noise.

Metal Banging

Ice build-up, loose parts, and sticks can cause a metal hitting metal sound. When you hear that noise, you should immediately shut off the unit. It frequently indicates that the fan blades are hitting an obstruction, which may damage the blades, fan, or motor.

It can also damage other components if blades break and fly off. The sound could also mean the fan has somehow shifted out of alignment, which could be the result of a loose part.

Tumbling Rocks

The sound of tumbling rocks or popcorn from a compressor isn’t good. It means that liquid refrigerant is entering the compressor, which can damage it.

Grinding Sound

A grinding sound often means parts need lubricant or cleaning – and then lubricant. The grinding can turn into a shriek or squeal if not maintained.

Gurgling 

Low refrigerant will result in a gurgling noise and is indicative of a leak too. It impacts performance and may damage components.

Shrill Shrieking

A loud, uncomfortable shrieking sound is a major concern. It could mean the compressor is experiencing higher pressure than normal, which is dangerous, and it should be shut off. Alternatively, it is indicative of dirty bearings, and that the motor is failing and needs to be replaced.

Loud Squealing

Dirty bearings can result in a loud squealing or shrieking noise. If it’s a new sound to your heat pump, then the motor or fan may be failing.

Loud Buzzing / Humming

If the heat pump should be operating but isn’t, and you hear a loud buzzing or humming coming from the unit, there’s a problem. The sound indicates an internal switch, relay, contact, or capacitor has failed or is stuck. It could also mean an issue with the motor.

Hissing

Hearing a hissing sound means there is a leak somewhere in the refrigerant system. If you can hear it, it’s loud and large, and your appliance is going to fail soon.

Bubbling

A leak in the refrigerant system may result in a hiss at the leak site or a gurgling noise within the lines due to a decrease in the refrigerant. This can damage the compressor and cause the heat pump to fail.

Fan Making Loud Noise

A fan making a clanking or clicking sound means a loose component, ice, or debris is interfering with the blades. It could mean the fan has shifted out of alignment due to a loose part or has already been damaged somehow. A squeal or squeak indicates the bearings are dirty or need lubrication.

Compressor Noise

A compressor that bangs or clanks has a loose piston pin, connecting rod, or another failing part. If it is a popping or stone rolling sound, the liquid refrigerant has breached it. A shrill shriek can indicate too much pressure in the compressor, and it could explode. Gurgling, bubbling or hissing can indicate a refrigerant leak too.

How to Quiet a Noisy Heat Pump

A heat pump should typically last for 12 to 15 years and will become louder as it ages. There are some maintenance steps and repairs that can be carried out to quiet noisy units. You may choose to do some repairs yourself, or decide to have professionals handle it.

Before picking up a screwdriver or wrench, sit and listen to the appliance run through several cycles. Attempt to identify the type of noise and location of origin. It may be difficult as one noise may mask others, or make it hard to pinpoint where the offending noise comes from. It could also be a situation where more than one component is too loud.

Once you have an idea of where the sound is coming from and what is making the noise, SHUT THE UNIT DOWN at the panel.

1. Examine the Unit to Find the Noise Source

Inspect the heat pump for loose or damaged parts that can contribute to the noise. Look for damage to the grill and housing, plus animal or insect nests. Check for screws and bolts that have become loose.

Look inside and see if there is visible damage, evidence of a leak, or a worn belt. Using a level, check out if the unit is level, and also if the fan is level. Spin the fan and observe if it has a wobble. Inspect the motor and fan drive-shafts and bearings for dirt or grease build-up too.

During the winter, snow and ice build-up can interfere with regular operation and result in both noise and damage. Keeping the unit clear will improve operation and protect the heat pump. It is also a good idea to seasonally check for leaves and sticks collecting on and around the unit and clearing animal and insect nests too.

2. Level Heat Pump

Leveling the unit may sound and be easy, especially if it is a minor adjustment. However, the copper connections that run between the building and the appliance are rigid and can crack or break if care is not taken. Check the bolts on wall mounted units, too, to ensure they haven’t vibrated loose.

3. Clean out Fan Blades

Clean and wipe dirt off the fan and blades – build-up can cause a flutter or wobble to occur. Make sure it spins freely, and blades aren’t damaged. If the fan is damaged or noisy, consider replacing it with a quieter one. There are several fans with quiet motors on the market manufactured to decrease noise.

4. Tighten Down Loose Screws, Nuts and Other Loose Parts

Make sure any loose screws, nuts, and parts are securely fastened. Don’t over tighten and break or strip fasteners. Ensure the refrigeration coils aren’t restricted, though, as they need to be able to flex some.

5. Replace Loudly Humming Electrical Components

Contactors have to repeatedly open and close and become dirty, worn, and louder with age. Contacts and relays can also wear with age and use, becoming burnt or pitted, causing a more intense hum. Replacement parts won’t break the bank.

The reverse valve is another component that can hum and vibrate noisily over time. The valve has an electromagnet (electric solenoid) that switches the unit between heating and cooling modes. This is an expensive repair.

Note: If you hear the cracking or arcing of electricity, shut the unit down and call for service for a potentially dangerous electrical issue.

6. Install Vibration Dampeners and Anti-Vibration Pads

Excessive compressor vibration can create extra noise and disturb you and your neighbors. Installing anti-vibration pads or vibration dampeners on the bolts securing the compressor should diminish vibrational noise.

 

7. Use Compressor Sound Blanket Wrap

Brinmar SBUHD Universal-Fit Air Conditioner Compressor Sound Blanket Wrap (#0421A)Compressors can get noisier with age. The louder sound may indicate that the compression ratio, refrigerant pressure, or charge should be checked.

If it is functioning correctly, consider installing a compressor sound blanket wrap around the noisemaker.

The blanket wraps over and around both reciprocating and scroll type compressors. It can reduce noise levels by more than 5dB, making it seem 40% quieter.

 

8. Build Sound-Deadening Enclosure for a Heat Pump

Most new heat pumps have noise ratings from 50dB to 95dB depending on size and manufacturer. However, there are a few models with ratings below 50dB. Installing a noise barrier could be a good solution. Always ensure there is adequate space around the unit for air circulation and access for maintenance and repair.

Building a privacy-style fence using wood or PVC planks may look nice, but it doesn’t offer much sound absorbency; it provides little sound reduction. Using insulated blocks or acoustic panels is a more effective barrier. Planting shrubs is a natural alternative and may look better than a constructed fence. Make sure to keep it, though, so it doesn’t interfere with the heat pump operation.

9. Call for HVAC Service

Sounds that are associated with low refrigerant, coolant leaks, or refrigerant in the compressor require a service call. Unusual or loud sound or replacing the heat pump motor may also be a reason to call for assistance.

If you’re not comfortable doing maintenance or repairs, then a service or maintenance plan may be of interest too. Always get a quote for service and repairs. If the heat pump is old, it may be more economical to replace it with a quieter model.

Conclusion

A quiet, efficient heat pump should provide years of winter warmth and cool summers. However, a noisy heat pump can disturb your sleep and cause neighbors to complain.

Regular maintenance and cleaning of the heating-cooling system can help minimize escalating noises. Tightening screws and nuts, securing or replacing loose or noisy parts, installing anti-vibration pads can all alleviate disruptive sounds.

I hope you have a better understanding of heat pump sounds, what may be their causes, and how they can be reduced. If you found this article interesting or helpful, let us know. Please share it with others who may also appreciate the information. As always, your comments and suggestions are welcome.

 

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