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Why Is Your Air Conditioning Unit Generating a Loud Buzzing Noise?

Every homeowner wants a quiet home air conditioner. The good news is that most AC units today are designed to operate as quietly as possible. However, some factors make it impossible to achieve silent running all the time. These include the equipment’s age, the location of its installation, and whether or not it is maintained regularly.


Over time, you may notice your air conditioner making some buzzing sounds – even if it was completely silent when first installed.

Although some of these noises are normal and just a result of its day to day operations, some are not, and may indicate problems with your air conditioner.

Possible Causes of Loud Buzzing Sounds from Your AC

If you notice loud, buzzing noises from your AC – loud enough to cause distractions in your household – it may be a sign that your equipment is not functioning properly and needs repaired.

Here are some of the probable causes:

Malfunctioning Compressor –

Your air conditioner’s compressor is the component in your cooling system that causes the refrigerant to flow through the evaporator coil, creating the cooling effect.

When you hear buzzing sounds, it may mean that the compressor is not performing its normal functions. It is also possible that the electrical voltage that flows through the outdoor AC unit may not carry the right amperage.

Damaged or Missing Isolation Feet –

The AC compressor is typically mounted at the base of the air conditioning unit. It rests on top of small rubber feet that are known as isolation feet.

After constant use over time, the isolation feet’s rubber sometimes disintegrates or develops cracks. This creates an imbalance on the compressor and can trigger a loud buzzing sound when you operate the unit.

Frozen Air Con Unit –

You expect to use your AC during the hottest days of the year.

However, your unit may freeze up when you need it the most. Freezing may be caused by a refrigerant leak and this can cause a buzzing noise that you can hear coming from your AC unit.

Loose Parts –

Your entire cooling system is complex, as it is made up of many working parts that are designed to work in sync to cool your room or home.

Even if only a single small part is missing or becomes loose, such as a bearing, it can affect other parts of the system. They may wear out prematurely and trigger the loud buzzing sound you can hear through your entire house.

Causes of Other Disturbing AC Noises

Aside from buzzing, your unit may produce other disturbing noises. These include the following:

Banging –

When you hear banging sounds coming from your AC, it is most likely a sign of a broken or loose part inside the compressor such as a crankshaft, piston pin, or connecting rod.

It’s also possible that the indoor blower is not balanced. Worst case scenario is you need to replace your compressor.

Clanking –

Another indicator of an unbalanced or loose part, clanking may mean either the failure of a part inside the sealed component or a loose compressor.

The outdoor fan or the indoor blower, including the blades, are hitting other parts. If ignored, the problem may only get worse.

Clicking –

Hearing electrical components clicking when starting up and shutting down is normal.

However, if it becomes persistent, it is unusual. It may indicate a failing thermostat or a defective control.

Your AC unit contains many electrical parts. Thus, it’s crucial that you address any potential issue right away. Otherwise, it may lead to more serious and costly repair in the future.

If you hear any disturbing noises from your AC unit as mentioned above, it’s best that you address the problem right away – before it gets worse! Call Spartan Plumbing, your local AC specialist.