Should Your Noisy Air Conditioner Bother You?

Posted: 2019-09-05

Any equipment that is noisier than it’s supposed to should be a reason for concern — that includes your air conditioner. Just like how coughing tells you there’s something wrong with your respiratory system, a noisy AC is letting you know it needs your attention.

Dealing with a noisy air conditioner can happen to any homeowner. In fact, it is quite common for your local HVAC company in Lino Lakes MN to receive such type of calls.


When an AC is working as it should, your air conditioner works almost in stealth mode — it should be virtually quiet. But if it’s excessively noisy, it means a certain part is loose or something restricts the airflow.

Investigating a noisy air conditioner can be quite challenging for an untrained individual because identifying where the noise comes from can involve disassembling the system. To ensure your safety, have a qualified technician check your AC unit.

Here are some sounds you may hear from your AC and their corresponding causes.


One of the possible causes of a loud banging or knocking noise from your AC is a loose part in the compressor, which houses the indoor unit. It could be in the crankshaft, connecting the rod or piston pin. Most of the time, this requires a compressor replacement; and in some occasions, it just needs tightening of a few screws.

An unbalanced blower fan can also cause your AC to produce a banging sound. The fan unit is usually located in the indoor part of the system, and when it’s unbalanced, it will create a knocking sound as the fan spins.

If it’s not the compressor or the fan, it could be that the compressor itself is loose, or parts inside the blower are hitting each other. This can be quite challenging to repair, so it is wise to call your trusted AC technician to address the problem.


There are a number of possible reasons for an AC to create a buzzing sound, including a faulty compressor. This part is responsible for pressurizing and cooling the refrigerant in the system. When it produces a buzzing sound, it could mean there’s a problem with the compressor itself or it is possible that the electrical voltage flowing through the outdoor unit is not properly set.

You may also hear a buzzing sound when your AC is frozen, especially if it has been running for long periods of time. In such a case, simply turn the unit off and let it defrost. After a few hours of being off, it should be running again without issues. However, if the sound persists, it could be that there is a refrigerant leak somewhere in the system, causing it to freeze. To properly address this issue, call a professional.

A buzzing sound can also be electrical in nature. A faulty contractor relay switch can also cause your AC to buzz. This is a low-voltage switch in the outdoor unit that is controlled by your thermostat. When it goes out, it creates a buzzing noise. Having said that, there could also be other electrical problems, such as loose electrical connections or aging wires. If not addressed immediately, this buzzing sound can worsen and may lead to more serious problems, including electrical shorts.


Of all the loud noises you will hear from an air conditioner, squealing is probably the hardest to ignore. This problem usually occurs in older air conditioners that use belts since newer models no longer use a belt system. Instead, they now use direct-drive motors without belts, which pull air across the condenser coils in your compressor.

When the belt begins to wear, it can slip during operation and create a squealing sound. If you have an older system, you will hear the sound both inside and outside of your home. Replacing the belt solves this problem.

Give Your AC the Care it Deserves

Whether your air conditioner creates banging, buzzing, or squealing sounds, or any other noise at all, entrust your unit to a qualified AC professional. Our technicians here at Four Seasons Air Specialists are factory trained and certified to diagnose problems and apply appropriate solutions. Our guys will ensure your AC works as silently as possible, giving you that priceless peace of mind. We are your trusted Centerville AC repair company serving you since 1974.