Have you ever encountered this problem where your aircon is humming but not turning on? Because if you have faced this problem, this article might give you a solution. Please read this whole article to find your answer.

There is a saying among people which states that “Nothing lasts forever, not even the best machines.” Air coolers are the best machines ever created by a human. This one invention worked like magic and also created history. We, especially the people who are living in high humid areas, it is quite unimaginable to think of living without an air cooler. It has become our essential need. But as I said no machines last forever. Sometimes your machines show early symptoms that its time has come to an end. Have you ever noticed why your air conditioner is humming but not turning on?

Today we will learn about this problem and will try to find its solution. I hope by reading this article you will find your solution. 

air conditioner is humming but not turning on

Why The Air Conditioner Is Humming But Not Turning On?

It happens because of your AC capacitor. When your capacitor stops working properly that’s when this problem occurs. 

So you need to change your capacitor if you need to solve this problem.

What Does It Mean When Your Air Conditioner Makes A Humming Noise?

It is absolutely not a big thing for your air cooler to make humming noises. But not every time. Sometimes it might happen because of misplaced features, sometimes it may happen because of overlooked refrigerant pipings which make unwanted shaking.

Sometimes it happens because of bad electrical functions etc. But if you unsee these symptoms it might take your aircon into more serious issues. 

How can you stop your air conditioner from humming?

If you are using your air cooler for a long time then this may cause your air cooler to make humming noises. If you want your aircon to stop making humming noises then all you can do is a simple thing, which is don’t use your aircon for an hour or so.

Turn down your aircon component to make it defrost. This will eventually stop your aircon from making a humming sound. 

What Do Capacitors Do In Ac? 

You can call your air cooler capacitor a powerhouse of your AC. You may ask why? Because capacitors work like a short time battery which helps to donate continual power so that your machine works evenly.

It basically helps the motor by continual electricity to supply uninterrupted power to your air coolers. This is the basic work of capacitors of your aircon. 

How Does Ac Pass Through The Capacitor?

The capacitors are attached right into the voltage area of an AC. As that voltage gets high or low the capacitor acts according to it by charging and discharging it. Then electricity will go along into the circuit from one side then another side. This is how capacitors work, it provides continual electricity to donate uninterrupted power to your air coolers. 

Will The Ac Fan Run If The Capacitor Is Bad?

By now we all know how capacitors work by providing continuous electricity to supply uninterrupted power to your air coolers. However, do you know that capacitors also help to keep the fan motor working? Yes, you heard me right. Capacitors help to keep the fan motor working, even help to start it. So if the capacitor is bad it means that your fan motor will stop working properly. Even a bad capacitor tightens up the fan motor which causes it to burn up. 

What Does A Bad Ac Capacitor Sound Like?

There are some things which will help you to find out if your aircon capacitor is bad. For example-

  1. Your aircon will stop producing cool air.
  2. You will face problems while starting your air cooler. 
  3. You will hear some unwanted noises.
  4. Your air cooler is gonna shut down on its own.
  5. You won’t be able to switch on your air cooler.
  6. You will get a higher electricity bill .  Etc.

What Happens When The Ac Capacitor Goes Out?

You might face some consequences if your aircon’s capacitor goes out. For example- 

  1. Application symptoms- Your aircon will stop providing cool air. You will find your air cooler is making humming or clicking noises. Once you turn on your air cooler it will eventually shut down on it’s own and maybe you won’t be able to turn it on again, higher electricity bills etc.
  2. Visual symptom- As the capacitor demean you will see it turns swollen because it’s usually flat on the upper side. Beside this thing, you will find some oily or sticky substance coming out of it. If you see or find these things it means you need to change your capacitor ASAP. 

How Long Does An Air Conditioner Capacitor Last?

Air cooler capacitors last at least 10-20 years. But here is the catch, it actually depends on how long it is gonna last. For example- If your capacitor is smaller than its actual size, if your capacitor is not made with good parts, if your air cooler cycles more than it has to, then your capacitor may not last long. 

How Can You Replace Your Air Cooler Capacitor?

You need to follow some rules if you want to replace your aircon’s capacitor. They are- 

  1. Safety first. Detach the electricity connection of your air cooler system. 
  2. Detach the excess panel to see if your AC capacitor is the reason for your problem. 
  3. Now write all the information of your old capacitor like how it was made or model number to make sure that you buy the right one for your replacement. 
  4. Dismantle the old capacitor but make sure that you give tags to the wires so that when you put your new capacitor you connect them into the right places. 
  5. Now you can fit your new capacitor in your old capacitor’s place and attach with the right wires. 
  6. After installing it now you can switch on the power mode and check if it is working properly or not. If it’s not working properly then again turn off your electricity and check your wires if you have connected it properly into the right place . 

So by following these steps you can replace your capacitor very easily. But if you are still hesitating to do so then don’t take any risks. Call a professional to do your job for you. Remember your safety must be your first priority. 

How Much Does It Cost To Replace An Ac Capacitor?

On average you can find your capacitor for $170. You can also find it in between $120 to $250. This includes the labour payment.  But if you want a good capacitor which comes with a good brand model, higher voltage then it might cost you around $400 or more. Also you have to pay some extra cash if you want a  professional installation. So your aircon’s capacitor cost really depends on you and which one you buy. It also depends on the brand, model and voltage. So it’s totally your call that which one you want to choose.  

What Causes A Capacitor To Fail?

There are many reasons behind the causes of your capacitor failure. For example- 

  1. Manufacturing defect. If your capacitor is made with made parts then your capacitor might cause failure. 
  2. If you don’t attach the right sized capacitor. 
  3. Dielectric breakdown. It happens if you don’t connect your capacitor properly with the right wires. This will create high voltage which becomes the reason for capacitor failure. 
  4. Open capacitor. If your capacitor over works then open capacitor will occur. And this open capacitor is one of the reasons behind capacitor failure. 
  5. Then comes the capacitor’s durability. It’s durability lowers down if heat increases. 
  6. As the heat gets higher, insulation resistance gets lower. This also causes capacitor failure. Lower insulation resistance also  brings many other issues for your air cooler.
  7. Higher heat also increases the pressure of the capacitor. You will find humid or liquid substances while you are gonna change your capacitor. 
  8. You will find weird noises coming from your capacitor. These noises also indicate that your capacitor’s life has come to its end. Etc.  


I hope by now you know why your air conditioner is humming but not turning on. I hope this article has helped you to find your answer. So from now on don’t get scared if your air conditioner is humming but check your capacitor if your aircon is not turning on.

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