Heat pumps are popular in Wausau as they provide an energy-efficient way to heat and cool your home. A heat pump uses a combination of electricity, circuits, moving parts, and fans to condition the air in your home. As such, it’s expected that the heat pump will make some noise. However, certain noises, like a whooshing sound, could either indicate that the heat pump is functioning as it should or could be a sign of a problem requiring repair.

Should My Heat Pump Be Making a Whooshing Sound?

During the heating season, you may hear your heat pump making a whooshing sound and simultaneously feel cold air being pushed out of the registers. In most cases, this indicates that the heat pump is functioning.

Your heat pump keeps your house warm by extracting heat from outside the home and then pushing that into your home. When the air outside is cold, the relative humidity increases. This humidity in the air can condense on the heat exchanger.

If the outside temperature is freezing or below, that moisture can turn into ice. If your heat exchanger is covered in ice, it won’t work effectively. This is when your heat pump needs to change to defrost operating mode to eliminate the ice. This change is what often produces whooshing sounds.

What Is Happening Inside Your Heat Pump When You Hear the Whooshing Sound?

When humidity, cold temperatures, and ice build up and trigger the defrost mode on your heat pump, it causes the unit to reverse the way it operates and go through a cooling cycle. This causes warm air to travel through the outdoor coil, temporarily warming the unit and melting the frost. This process continues until the outdoor coil hits approximately 57°F.

The defrost mode is necessary because, as your heat pump functions, it uses the heat exchange properties of the refrigerant to move the heat from outside to another space. As heat energy is eliminated from the outdoor space, the temperature in that area drops. This will cause the moisture around the coils to develop frost, making it difficult for them to extract heat from the air. The defrost mode allows the unit to remove the ice and function normally.

Having your heat pump go into defrost mode on days when the temperature has dropped significantly indicates that the unit is working as it should. Warm air should still be blowing into your house, and you should hear the typical humming sound coming from the heat pump.

Under normal circumstances, the defrost cycle and its accompanying whooshing sound will last about 10 minutes. It should not activate more than twice an hour. If you notice that your heat pump is going into defrost mode frequently or if it’s happening on warmer days, this indicates an issue with the unit. You’ll need to get professional help from the HVAC professionals at Southport Home Services.

What Causes the Whooshing During Your Heat Pump’s Defrost Mode?

The sound you hear is caused by a valve that reverses your unit from heating to defrost mode. The unique thing about a heat pump is that it can heat a home during the winter, but then the process can be reversed to cool the house during the summer. When your heat pump is in defrost mode, it is as if it switches from its heating to air conditioning function.

This allows heat to get directed outdoors to remove the ice from the exchangers. During this process, you may experience a quick blast of cold air through your supply registers.

Your heat pump will switch back to heating mode when the ice is gone. You should again hear the whooshing sound as the refrigerant flow is reversed. Avoid the temptation to turn off your thermostat when you hear the defrost mode happening. This will only make the ice removal process take longer.

When ice builds up on your heat pump, it is a lot less effective. If it can’t defrost properly, the unit will eventually be damaged. Along with the whooshing noise, you might see steam coming off your heat pump or water dripping from it as it defrosts. This is a normal part of the defrost cycle and should not cause any alarm.

Other Reasons Your Heat Pump Is Making a Whooshing Sound

If air is trapped in your heat pump, you may hear a whooshing or gurgling sound. An easy way to check this is by feeling the heat pump’s radiator.

If the radiator is cold on the top but hot at the bottom, it has air trapped inside. Hot air rises to the top of the radiator and inhibits hot water from circulating properly, leaving you with an inefficient heating system. Since the water can’t travel freely through the radiator, it overheats and starts to make gurgling or whooshing sounds. You can fix this problem by having an HVAC technician bleed the unit.

Additional Problems That Could Make Your Heat Pump Noisy

If your heat pump makes loud whooshing, banging, or gurgling sounds, but you have not noticed frost or ice on the outdoor unit, there could be something wrong.

A refrigerant leak can lead to you hearing a bubbling or hissing noise from the heat pump. Loose fan blades might hit the side of the metal casing, creating a banging sound. Loose nuts or bolts in the unit can cause a vibrating or rattling sound.

Electrical issues can produce loud humming, buzzing, or droning sounds. Your outdoor fan motor may be exposed to humidity, which leads to a breakdown in the lubricating oils needed so that the motor runs smoothly and quietly. A dry fan motor will produce a loud grinding or shrieking sound when the pump runs.

A heat pump is designed to last for around 15 years. If your unit is 15 years or older and is making noise, it could indicate that some of its essential parts have worn out and need to be replaced. If you think you have one of these issues, contact the technicians at Southport Home Services. We are happy to evaluate your system and let you know if it’s best to repair damaged parts or replace the unit entirely.

During our annual maintenance visits, we can discuss ways to get your heat pump to run more quietly. This could include installing a discharge muffler, using compressor grommets, insulating compressor compartments, or changing fan blades.

If it’s time to replace your system and you want something quieter, you may want to consider a variable-speed compressor. This operates a lot quieter than a single-stage compressor. Our technicians will be happy to discuss all of these options with you.

Enjoy Climate Change on Demand in Wausau, Wisconsin

At Southport Home Services, our NATE-certified HVAC team is proud to be a one-stop repair shop for all your HVAC needs. We are proud residents of the Wausau community and are committed to doing work that makes the community proud. We have an A+ Better Business Bureau rating, an award-winning team of technicians, and are factory-authorized Carrier dealers.

Our services include HVAC installation, maintenance, and repair services. We also offer general plumbing repair, installation, and maintenance services and are equally comfortable working in residential and commercial spaces. Contact Southport Home Services today to learn more about our products and services.

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Thomas Suchla
Thomas Suchla


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