Air Conditioner Buzzing When Off: 4 Surprising Reasons!

Have you ever heard your air conditioner buzzing when off? Well, there is more than 1 meaning on why this happens. First, you might want to stop everything that you are doing once you hear a buzzing sound.

You may panic about why does this thing happen. But don’t worry, a simple buzzing from your AC unit may indicate a simple repair.

air conditioner buzzing when off

You must never ignore any sounds coming from the AC unit since it could lead to bigger problems in the future.

There are many more things that you should know about your air conditioner, especially if it’s buzzing. So, without further ado, let’s start!


AC Buzzing When Off

If you wonder why your air conditioner is buzzing when off, well, it is a sign that something is wrong with your AC unit. Here are some probable reasons why the air conditioner buzzing when off.


Reason #1. A frozen unit

If you are using you’re air conditioner for a long period; it tends to freeze inside. The freezing will create a buzzing sound. When buzzing occurs due to freezing, the most effective solution is to thaw. Then, please turn it off and let it stay that way for a few hours for the freezing to melt.

After thawing, your air conditioner should work fine when you switch it back on. The freezing occurs due to the refrigerant leaks making it freeze. If it happens frequently, and it happens for a few more hours, call for a professional to fix it.


Reason #2. Loose parts

Your Air conditioner consists of many parts. Although it is a given in every appliance, there will come a day when some of these parts become loose. It may seem like no big deal has loose parts inside, but note that these small parts are responsible for a good and working unit.

Missing some of these small parts or having some of them loose may result in an insufficient air cooling experience or may damage your AC unit.


Reason #3. AC condenser fan not working

Another reason why your AC unit is buzzing is because of its condenser fan. The condenser fan is responsible for blowing the cool air out. If the blower inside doesn’t work, but the fun does, the fan will create a loud buzz. The buzz may also be caused by small falling debris reasons for an immobile fan.


Reason #4. Electrical issues

Your AC may have small electrical issues causing it to buzz even when turned off. Having this issue is also one of the main reasons for the buzzing sound. Well, one of the easiest electrical repairs that you could do is replacing the contactor relay switch. It is a low-voltage switch located on the exterior part of the unit controlled by the thermostat.


Types of Noises

If you have noticed that your AC unit produces loud noises, it is a sign that something is not right. If you have a hard time distinguishing each noise that your air conditioner makes, here are some guides.


Type #1. Banging

A banging noise coming from your air conditioner is usually a sign of loose or broken parts inside. It could either be the piston pin, connecting rod, or the crankshaft inside the compressor. Banging noise may also be a sign that you have to replace your air conditioner compressor already.


Type  #2. Clanking

A clanking sound is another sign of a loose part or broken component inside the AC unit. A compressor may also be one of the problems. The sealed parts are most likely have failed and loosened up.


Type #3. Clicking

A clicking sound may be heard whenever you start any electrical components such as Air conditioners. Although this may be true, a constant clicking and continuous clicking sign that something is wrong.

It could be caused by a defective thermostat or a failing control component in the system. This is critical for the most electrical unit because it could lead to electrical issues or may result to fire if left untouched and unrepaired.


Type #4. Buzzing

Buzzing in AC units is an alarm system that notifies if something is wrong with the AC unit. It could be caused by loose parts, debris, fan failure, or if your Air conditioner unit needs repair.


Type #5. Squealing

A squealing sound may come from your AC unit if the fan motors are bad or are failing. The blower wheel also squeals if the motor is malfunctioning. It may sound normal at initial start-up, but it is not okay after continuous use.


Type #6. Humming

Humming AC units are not that serious, although it also warns you that something is wrong. For example, a loose part in the refrigerant piping could cause vibration that makes the AC seem humming. It may not look like anything serious, but if you leave it like that for a long time, it could lead to a more serious maintenance issue.


Type #7. Chattering

You may start to hear your AC produce a chattering or a rattling noise, especially if your unit is already old. It can also be caused by twigs or leaves trapped inside the unit. An electrical contractor may also make the clattering sound.


Type #8. Screaming

If you ever hear screaming like high-pitched screaming, you might have to call the professional right away. Internal pressure in your compressor may also produce a high pitch sound. Do not panic when your unit turns off on its own.



So if you ever find your air conditioner buzzing when off, you don’t have to panic right away. Instead, knowing these little things will make you feel calm whenever you hear these coming from your AC unit.

1 thought on “Air Conditioner Buzzing When Off: 4 Surprising Reasons!”

  1. Not any of those loud noises. Just a noise like air flowing. Even when I turn off the thermostat. ???

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