Are Heat Pumps Noisy? A Texas Technician Answers
January 09, 2020
Considering a heat pump for your home? Or wondering if your current heat pump is too loud?
We’ll explain how much noise is considered normal for a heat pump.
Most heat pumps produce sound between 50 and 90 decibels. The higher the decibel rating of the heat pump, the more noise it will make during normal operation.
The quietest heat pumps on the market run as low as 50 decibels, which is equivalent to the sound of a conversation at home or light traffic. Louder heat pumps (70–90 decibels) make noise equivalent to the sound of a dishwasher or garbage disposal.
However, it’s common for heat pumps to run louder than their advertised sound rating under certain conditions, especially during the defrost cycle.
In this article, we’ll explain:
- Why heat pumps are noisy during the defrost cycle
- Problems that make a heat pump noisy
- How to make your heat pump quieter
Why heat pumps are noisy during the defrost cycle
During the winter, your heat pump will occasionally need to use its defrost cycle to melt frost that forms on the outdoor unit. The defrost cycle will automatically start when the system detects frost or ice on the outdoor coils.
When the defrost cycle starts, it’s not uncommon to hear a loud whooshing sound that lasts for a few seconds. This is the sound of the reversing valve changing the flow of refrigerant in your system. Reversing the flow of refrigerant allows your system to bring heat to the outdoor unit, which will melt the frost/ice.
After the initial whooshing sound, you may also hear the outdoor unit working a little harder than normal. Once the defrost cycle is complete, your heat pump should return to its normal sound level.
Problems that make a heat pump noisy
If your heat pump is loud and you don’t notice any frost or ice on the outdoor unit, then your heat pump may have a problem that’s causing it to make a loud sound.
Some common problems that cause your heat pump to make loud noises include:
- Refrigerant leak(s). This is usually the issue if you hear a hissing or bubbling noise coming from your heat pump.
- Loose fan blades or other parts. Sometimes fan blades become loose and hit the side of the metal casing, creating a loud clanging sound. Additionally, loose nuts and bolts inside your system can cause a vibrating or rattling sound.
- Electrical issues. If you hear a loud buzzing or humming drone, you may have an electrical issue that a professional should fix ASAP.
- Dry fan motor. Sometimes the outdoor fan motor can get moisture inside of it, which breaks down the lubricating oils that help the motor run smoothly and quietly. If you have a dry fan motor, you’ll hear a loud shrieking or grinding sound while your heat pump is running.
- Old age. Older heat pumps (15+ years) will likely make more noise than new systems because parts wear out over time.
If you think you have one of the issues above, you’ll need to contact a professional to repair your heat pump.
How to make your heat pump quieter
Besides contacting a professional to fix any issues that could be causing your heat pump to make loud noises, an HVAC professional can also install some noise-canceling features for your heat pump.
Examples of noise-canceling features include:
- Insulated compressor compartments
- Forward-swept fan blades
- Compressor grommets
- Discharge muffler
If you’re in the market for a new heat pump, you can also consider a variable speed compressor, which operates quieter than a standard, single-stage compressor.
Interested in a quiet heat pump for your home? Or want a professional to fix your loud heat pump?
We can help! We offer exceptional heat pump installations and reliable heat pump repairs. When you hire Reliable Air for any HVAC service, you can count on courteous technicians who will get the job done right—the first time.