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Why Does My Heat Pump Make a Buzzing Noise?

Two identical heat pumps covered with snow

Heat pumps are a great alternative to traditional heating and cooling systems with a separate furnace and air conditioner. If this is your first home with a heat pump, you might notice some things you’re not used to, such as a heat pump that is buzzing or making other noises.

It is not uncommon for a heat pump to make noises, but which noises it makes are key to learning what the problem is. Call A+ Heating & Cooling  Electrical for a heat pump tune-up so you stay comfortable year-round.

Common heat pump noises

A heat pump looks like an air conditioner. They are big boxes with a large fan inside and are located outside. Like an air conditioner, it is common for a heat pump to make some noise. Usually, heat pumps are located in an area outside where you most likely can’t hear it, but if you hear any of the following loud noises, there’s no cause for alarm.

Startup and shutdown noises

When the refrigerant in the heat pump changes from a liquid to a gas, there is usually a startup noise. Some people notice that when their heat pump starts, it sounds like an out-of-balance washing machine. This noise is caused by the compressor and it can be loud, but it should stop after a few minutes. Your heat pump might make similar noises when it shuts down, too.

Defrost mode noises

Heat pumps can also keep us warm in the winter. However, being outside in the cold can cause some parts to freeze over. Luckily, a heat pump can defrost itself to combat the cold. If it is very cold, you may hear your heat pump go into defrost mode multiple times. It is normal to hear your heat pump make a “swooshing” sound every time this happens.

Humming or buzzing noises

As electricity runs through your heat pump, you can hear humming or buzzing noises. This is normal, as there are a number of coils and contractors that are known to hum as electricity runs through them.

Fan motor noise

As the fan in your heat pump kicks on, it can be noisy but is not often bothersome. This sound should be consistent and smooth and not obnoxiously loud.

Ways to keep your heat pump quiet

If your heat pump is in a location where you hear it frequently, there are a few things you can do to stifle the noise. First, see if you can find out the age of the heat pump. Heat pumps have an average lifespan of 10 to 15 years – and if yours is older than that – it may be time for a replacement.

Having regular maintenance performed annually on your heat pump will help extend its lifespan and prevent future repairs. A trusted heat pump technician from A+ Heating & Cooling – Electrical can inspect your heat pump and replace noisy or loose parts like fans and motors. Ask your heating and air conditioning technician about compressor sound blanket wraps and vibration isolation dampener mounts to help quiet some of the noise as well.

Uncommon heat pump noises

Now that you know what loud noises are normal from a heat pump, it’s important to know what sounds to listen for to learn when your heat pump has problems and might need repairs from a professional contractor.

  • Whistling sound inside when your heat pump is operating
  • Rattling noises, perhaps from debris, leaves, or branches contacting the fan blades inside the outdoor unit
  • Metal-on-metal sound
  • Vibration
  • Loud humming
  • Hissing noise from a stuck reversing valve
  • Repeated gurgling noises, perhaps from low refrigerant caused by a refrigerant leak. A refrigerant leak should be inspected immediately, as it can cause damage to your unit and the environment. If this is the case, shut or switch the system off and call a professional technician to fix the problem
  • The unit makes a loud shriek when the motor is running
  • A banging sound from a loose fan blade

If you hear any of these noises, try changing the air filters first. If noises still persist, turn off your unit and inspect it. Clear it of any outside debris. You can also try to tighten loose bolts and screws to stop rattling noises. If you’ve done all of this and your heat pump is still making noises, call A+ Heating & Cooling – Electrical right away.