Air Conditioner Sounds Loud: Noises You Should Not Ignore

A look at any catalog of articles on heating systems and modern central air conditioning and utilize two-stage or variable-speed motors that are designed to create minimal noise. If you notice loud sounds coming from your central air conditioning systems it is a sure sign of an issue with its operation that can be moderate or severe.

There can be a number of reasons why your AC Conditioner sounds loud. The first step toward correcting the problem is determining what is causing it. Let’s take a look at noises you should not ignore and how to correct them.

If Your AC Is Making Banging Noises

If Your AC Is Making Banging Noises

The compressor in your HVAC system is designed to distribute refrigerant to various components of your unit in order to remove excess heat from your home. If you are hearing a banging noise, it can be a sign that the compressor is experiencing a problem. It is not unusual for parts of the compressor to become loose, especially if you have an older system.

The sound you are hearing is caused by parts that have become loose or detached and are hitting the compressor’s housing. In most cases, compressors aren’t easily disassembled, making them irreparable.

Contact a qualified technician at an HVAC company to evaluate the situation and make repairs. In some instances, this may not be possible and you will require a new system.

If Your AC Is Screeching

If Your AC Is Screeching

The usual culprit associated with screeching noises coming from your HVAC unit is the fan motor located in the exterior condenser unit. This fan is responsible for removing heat from the refrigerant.

If you are hearing a high-pitched screeching or shrieking noise, the cause can usually be traced back to this fan. In some cases, it may be caused by a damaged motor in the condenser system’s compressor.

Another cause may be that the blower fan motor located inside your home has become damaged. This fan collects warm air from the interior of your home and sends it through the return ducts to be cooled by your air conditioning system for redistribution. The blower fan performs this function, as well, by circulating warm and cool air back and forth through the unit to cool your home.

You might also find that the screeching is caused by damaged bearings or fan belts in your fan motor. This is usually the case when the screeching sound is emanating from the HVAC components inside your house.

Any of these require a service call. It is best to turn off your HVAC system and contact a professional to address the problem before turning it back on.

Constant Humming

Constant Humming and Air Conditioner is Loud

If your contactor relay switch has become defective it can create the humming sound you may find yourself hearing from your HVAC system. This part is responsible for starting the exterior condenser unit as signaled by your thermostat. This electrical problem is something that must be addressed immediately.

Turn off your system and contact an HVAC technician to investigate the situation. Failure to do so can result in severe damage to your system and expensive repair, if not irreversible damage.

Loud Buzzing Sound

Loud Buzzing Sound of Air Conditioner

You should never allow buzzing noises coming from your HVAC system to go unchecked. Buzzing is a warning that a fan blade has loosened or gotten off the balance in your condenser unit. This buzzing sound can also be created by faulty outdoor fan motors, condenser coils that have gotten dirty, and loose parts. 

If an obstruction is located near the copper lines of your system, it can also make this sound while in operation. The direst of causes is a refrigerant leak. Refrigerants can be very dangerous and must be dealt with immediately.

The best solution is to ensure that you keep up with maintenance to prevent any of these issues from occurring, but if you do hear a buzzing noise, contact a professional immediately to correct the problem and prevent additional damage.

Regular Rattling

Regular Rattling of Air Conditioner

There can be a very simple reason for rattling. Loose sticks, dirt, or leaves can sometimes become lodged in your exterior condenser unit and cause this problem. It can be remedied by turning off the system and removing the offending items.

In some cases, rattling may be a sign that there is a damaged electrical contractor present in your system. If you were unable to locate any visible items hindering the operation of your condenser unit, then this may be the problem. This issue can be quite significant.

Contact an HVAC expert to have this corrected in order to avoid suffering more severe harm to the central air conditioner’s compressor.

Intermittent Clicking

Intermittent Clicking of Air Conditioner

A clicking noise can sometimes be heard when your HVAC unit comes on or off. This is entirely normal and nothing to worry about. If you are hearing more continuous clicking, that is an issue. One potential cause is a malfunctioning thermostat. An experienced technician should be able to diagnose and replace or repair your thermostat with relative ease.

Constant Hissing

Air Conditioner is Constant Hissing

Hissing is usually the result of an air leak. If the leak is severe enough that you are hearing the hiss, then you should have it checked immediately. Air leaks of this magnitude can be costly as they directly affect the energy efficiency of your system and interfere with heating and cooling operations.

Hissing might also be the result of a faulty expansion valve or an incompatible air filter. It is best to call a qualified HVAC technician to inspect your system and make any necessary repairs.


There are several types of sounds your air conditioning system might be making, and they might point to a variety of potential issues. The scale and complexity of the fix will vary depending on the issue and the unique circumstances around your home, so even with these tips, you may not be able to fix the issue.

In situations like this, it’s best to contact a local HVAC professional to get assistance with your loud AC, as they’re trained and experienced enough to solve the issue quickly and efficiently.

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Nishant Desai
Nishant Desai
Nishant Desai has over 8+ years of experience in SEO and blogging. His blogging expertise can organically increase online visibility and traffic for blogs and websites. With his SEO expertise, he has already contributed to iGeeksblog, Firstsportz, and Firstcuriosity. In addition, he can create content strategies, conduct keyword research, publish optimized blogs, and resolve technical issues.

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