Heat Pump Noises - The Good and the Bad in 2024 | DIY Home Comfort

It's pretty common for your heat pump to make some noise.

Just like your air conditioning system, your heat pump is made up of a few different systems, all with pumps and fans contained within them. It's unrealistic for those to make no noise at all.

A modern heat pump system will run between 70 - 75 decibels. 70 decibels is equivalent to the noise generated by an average office. The quietest a heat pump unit can operate at is 40 - 50 decibels.

To give you an idea of how quiet that is, you can hear rustling leaves at about 30 decibels. So unless you are standing right next to a heat pump unit, it will be tough to hear.

This also applies to ductless mini-split heat pumps. A ductless mini split is similar to a central air conditioning system but without ductwork.

With a central AC system, cold air is generated at a single point, that being your indoor air handler and distributed throughout your home via ducts.

A ductless heat pump uses an individual fan and evaporator unit to generate cold air in each room they are mounted.

📘 Related Reading: The Ultimate Guide to Ductless vs Ducted Heat Pump Systems

When your heat pump starts up and the fan kicks in, you might hear a rattling noise.

When the compressor kicks on and compresses the refrigerant for the next cooling cycle, you will hear a vibrating noise.

These noises should cease after a few minutes, dependent on where your heat pump is in the cooling or heating cycle.

These shouldn't be loud noises but normal operating noises that should be consistent over time.

Your heat pump is powered by electricity, so it's normal to hear the humming of buzzing sounds as electricity courses its way through the HVAC unit.

There are a bunch of electrical components that make some noise while in operation.

Heat pumps are popular as they keep you warm in winter and cool in summer.

However, if it's too cold outside, your heat pump can stop being effective under a certain temperature.

To stop the outdoor evaporator coil from freezing over in extra cold weather, your heat pump will go into defrost mode.

It is normal to hear a swooshing sound every time your heat pump goes into this mode while it tries to stay warm.

Hopefully, so far, you have learned to recognize the normal noises that your heat pump makes during normal operation.

Now for the fun part. What do you do if you start hearing loud noises that don't sound normal?

Well, it's probably time to call in that HVAC technician for an HVAC repair or service.

So what are some of the noises we shouldn't be hearing:

• Constant whistling sound
  
• Loud vibrating sound
  
• constant gurgling noises
  
• Metal on metal or loud shrieking sounds
  
• Hissing sounds
  
• Constant rattling noise
  

If you start hearing any of these noises, it's time to investigate. Whistling sounds could be from damaged ductwork, so they are more than likely coming from your attic space or inside your walls.

Vibrating sounds could be from improper mounting of your indoor and outdoor unit or its internal components. 

Metal-on-metal sounds could be from fan blades hitting the side of the unit or ice if it's frozen over. 

Loud shrieking sounds similar to metal-on-metal sounds are definitely not healthy. These could be caused by loose parts interfering with moving parts or dirty motor bearings.

Gurgling sounds could be from a low refrigerant charge as its struggles to compress enough gas for the next operation in the heating and cooling sequence.

If you hear any of these types of sounds, it's time to call in the professionals.

The first thing we always advise is to check and replace your air filter to take it out of the equation when troubleshooting an air conditioning or heat pump system.

A new heat pump system will, of course, be quieter than an older system, but it will still make some noise.

The location of the outdoor unit can affect your family if it's located very close to a bedroom window. 

If you hear vibrating sounds penetrating your home, your heat pump might be mounted to your home structure instead of on its own pad.

As a heat pump ages, vibrations can travel through that connection to your home, making it seem louder.

The best way to keep your heat pump quiet and working efficiently is to conduct regular heat pump maintenance through a professional HVAC service company.

The occasional loud noise may be a one-off, but if you hear them more often than not, it's time to identify why you have a noisy heat pump.

Repairing is generally the first thing that makes sense regarding strange noises.

This makes sense presuming your heat pump or AC system is in good working order.

However, the age of your HVAC system plays a factor when making this decision.

A heat pump will generally last 10 to 15 years.

If you are close to that number and require an expensive part replacement, such as a compressor, it may be cheaper in the long run to replace the entire unit.

As per the above comment, there are occasions when it makes more sense to replace the whole unit.

If a part replacement and repair cost more than 1/3 to half of the cost of a whole unit replacement, it might be worth it.

When you factor in the additional savings through installing a more energy-efficient unit, this can make more sense.

Moving a heat pump unit to reduce noise can be more difficult than its worth.

Moving and reinstalling is a technical and time-consuming process and an expensive one.

Moving a unit can be done though you are limited to how far away from the building it can be.

Generally, we recommend one of the two options above before thinking about moving a noisy heat pump.

Hopefully, we have helped educate you on some of the sounds you are most likely to come across if you have a heat pump.

We like heat pumps, but they should be seen and not heard. 

If your heat pump is making noise that just doesn't sound right, it's time to call in the cavalry.

Check out your local HVAC services companies online, and don't forget to check out their reviews to ensure you get the right contractor for your heat pump problems.

📘 Heat Up Your DIY Skills! Learn more about your home's heating system in our detailed homeowner articles!

Scott Harding

Scott is the main author of DIY Home Comfort. He's also an experienced HVAC technician that enjoys home renovation and spending time with his family. You can find out more about him here.