Air Conditioner Making Noise When Off: What to Do When This Happens?

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Air conditioner is one of the greatest inventions we ever encounter. This appliance will surely be beneficial during the summer when the heat strikes you like never before. But, what if air conditioner making noise when off? Does that mean we need a new replacement?

Noises You Heard When Air Conditioner is Turned Off

To understand better about why your air conditioner makes weird noises when it you try to turn it off, first you need to make sure where the noises come from.

In general, the noises coming from your air conditioner may be heard from inside the house, or simply from outside. The cause will be different as well.

If the noises come from inside the house, it may be:

  1. Your air filter is banging against the grille.

When air conditioner making noise when off, one factor causing that to happen is your air filter slamming the grille. This can be caused by various factors, such as:

  • too ‘restrictive’ air filter, which is marked by a MERV rating of 10+
  • dirty air filter, or
  • undersized return ducts.

If your air filters feels ‘too restrictive’, then it is a great decision to replace the filter with a less restrictive one. Or you may upgrade your air filter into an air scrubber. However, if you have a dirty air filter, you need to clean that or simply replace with another one. If the problem lies in those undersized return ducts, which may influence the air speed when going through the returns, you may need to call an AC repair guy to conduct a new ductwork.

  1. Damper problem

Some air conditioners have dampers which are in charge to alter the airflow amount that is flowing to various home parts. The noise may be the result of the closing damper once your AC system shuts off.

For this problem, you don’t have to do anything, as this is basically a normal operation. However, if you think the bang sounds loud and disturbing, consider calling your favorite HVAC guy to have a check on it.


  1. There is a problem with the fan.

This as well becomes the problem causing a weird noise coming from your AC when shutting off. If this happens, consider calling the professional to know whether you need just a repair or a total replacement.

If the noise comes from outside, there are two factors causing this to happen:

  • The internal support springs of your compressor are broken

In order to fix this, you may not do it yourself. This problem seems to be able to fix if you are replacing the compressor as whole, and that can be expensive! So, it is recommended to leave it per se if your unit is not under warranty. This can be done since your unit may not fail to operate in any short future.


  • Fan knocking the unit

The outdoor part of your AC also has a fan in it. If parts of your fan loosen, then the fan itself can bang the unit, causing a disturbing noise to emerge.


For a quick fix, you may consider replacing your fan with a new one. Or, you can simply tighten the bolts if you are under a tight budget.

So, those are what you can do when air conditioner making noise when off. Of course, it’s easier to just call the professional to have the unit checked. However, it’s always great to learn such knowledge, isn’t it?