6 Reasons Why Your Outdoor HVAC Unit Makes Loud Noises

No one wants to hear a loud noise coming from their outdoor HVAC unit, especially if it’s late at night.

Unfortunately, many homeowners experience this problem and are unsure of why it’s happening.

Is your outside HVAC unit making loud noise? In this blog post, we’ll discuss some of the most common reasons why your outdoor HVAC unit makes loud noises. We’ll also supply you with some tips on how to fix the issue. Keep reading to learn more!

Before getting started, you can check out this post from the team at Anderson Air if you’d like to learn about the importance of HVAC plenums.

Outside HVAC unit making loud noise — Six reasons why

Here are six reasons why your outdoor HVAC unit is making a loud noise:

Reason #1 — Outdoor HVAC unit making loud noise because the fan belt has come loose


If your outdoor HVAC unit is making loud noises, it could be due to a number of different reasons. One possibility is that the fan belt has come loose and is hitting the fan blades. This can create a lot of noise and can also damage the fan blades over time.

Continuing to use a system with these problems can cause further damage and may end up costing you more money in the long run.

Reason #2 — The compressor is overworked and needs to be replaced

One of the most common reasons your outdoor HVAC unit makes loud noises is because the compressor is overworked and needs to be replaced. The compressor is responsible for circulating refrigerant throughout your system, and when it starts to fail, it can make a lot of noise.

If you notice that your outdoor HVAC unit is making loud noises, it’s important to get it serviced by a professional as soon as possible. A professional HVAC technician will be able to quickly assess and identify the problem. They can also recommend the best course of action to solve the issue.

Reason #3 — The refrigerant levels are low which is causing the compressor to work harder than it should


Speaking of the compressor in your HVAC system, another reason why it might be making loud noises may be due to the fact that the refrigerant levels are low. When your HVAC system’s refrigerant levels are low, it can cause the compressor to work harder, which can result in an unwanted or unpleasant noise.

Reason #4 — There’s a problem with the airflow which can be caused by clogged filters or a blocked vent

In some cases, a blocked vent can also cause your HVAC unit to make a loud, unwanted noise (regardless of its age).

If you suspect that there is a problem with your HVAC system’s vents or air filters, it is important to reach out to a professional service as soon as possible. With proper maintenance, you can help prevent problems and extend the life of your system.

Reason #5 — The outdoor HVAC unit is too close to trees or other objects which is causing it to vibrate

If your outdoor HVAC unit is too close to trees or other objects, it may cause it to vibrate.

The unit should be at least two feet away from any objects, including trees, shrubs, and buildings. This will help reduce the vibration and prolong the unit’s life.

In addition to this, the outdoor unit should be level and stable. If your HVAC unit is not level, it will begin to vibrate more often and may eventually break down, leaving you without a working unit.

Finally, make sure that the coils are clean and free of debris. A build-up of dirt and dust can cause the unit to overheat and break down.

Reason #6 — Outside HVAC unit making loud noise because there’s something wrong with the motor or bearings


If you happen to hear a humming noise coming from the HVAC unit on a regular basis, it could be that the motor or bearings are going bad.

The first thing to do is check the motor. If it’s running too hot, it could be seized up. To assess the severity of the issue, you can try to spin the blades by hand. If they’re hard to turn or make a grinding noise, the motor will need to be replaced.

If the outdoor HVAC unit’s motor seems to be working properly, then it’s most likely the bearings. These can also seize up if they get too hot. To replace them, you’ll need to take apart the housing and remove the old bearings. Make sure to clean out any debris before putting in the new bearings in the outdoor HVAC unit.

Outdoor HVAC unit started making loud noise solutions 101


If your outdoor HVAC unit is making strange noises, the best solution is to contact a reputable technician as soon as possible. These technicians can help you determine the cause of the noise and fix the problem.

More often than not, you can deal with these problems without having to replace the entire unit. By taking care of the issue early, you can avoid further damage and costly repairs.

Have you had any issues with strange noises coming from your outdoor HVAC unit? Contact an HVAC technician today to stay cool and comfortable over the coming summer months!

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