With the ever-rising temperature and unbearable and scorching heat, air conditioners have become a necessity in modern times. Almost every household, office, school, institution, and other places have air conditioners. It helps people to escape the immense heat and provide them with comfort.

But what if you get into an air-conditioned room after bearing with the heat and find the device not working? Facing problems with your air conditioner is one of the most common and worst things that one can face.

What Are the Common Reasons for Air Conditioner Not Cooling? How to Fix Them?

Problems with air conditioners may arise due to a number of reasons. Here are some of the causes that may lead to the malfunctioning of the air conditioners. Read on to find out the causes and how to fix them:

1. Dirty Air Filter

This is the most common reasons why your AC is not cooling enough. A problem with the air filter of your air conditioner can lead to cooling problems. Sometimes, the accumulation of debris and dust can reduce the cooling capacity of the air conditioner.

Keep AC Filter Clean
A Choked AC Air Filter Will Result in Poor Cooling

But luckily the issue can be resolved very easily. All you have to do is open the front panel of your AC and take out the dust filters. Clean them under running water with a soft brush. The air filter needs to be checked from time to time and cleaned.

2. Accumulation of Dirt on the Condenser Coils

Condenser coils getting dirty can also affect the cooling of an air conditioner. It is the condenser coil which takes up the heat and transfers it outside. The condenser unit, being exposed to all kinds of dirt and debris, can cause it to get dirty.

Dirty Condenser Coils Reduce Cooling
Keep Condenser Coils Clean for Better Cooling

The problem becomes more severe if your house is close to a construction site or a place where a lot of dust flies in the air. This dust sticks to the condenser coils and reduces the effectiveness of condenser which in turn, affects the cooling largely. It also increases the consumption of energy.

You should keep the condenser coils clean or take the help of a trained AC technician for a thorough service of your air conditioner.

3. Low Level of the Gas/Refrigerant

The low refrigerant level also results in poor cooling. If the amount of refrigerant in your air conditioner is low, the amount of heat trapped in the device will be more and it will become very difficult to cool the place.

The most common cause, of split AC not cooling enough, is the low refrigerant level because of a leak in the condenser or evaporator coil or the connecting pipe between the indoor and outdoor unit.

As compared to window ACs, split ACs are generally more prone to refrigerant leakage because of the extra length of the pipe and more exposure to the outside environment.

Gas Leakage
Formation of Ice Crystals Due to Low Refrigerant Level

There is no easy way to check the level of refrigerant left in your air conditioner. But if your AC is not cooling properly and if you suspect it may be because of refrigerant leak then you can check for some signs like bubbling or hissing sound and formation of ice crystals on the connecting pipe or the evaporator coils.

If the refrigerant level is low then you will have to seek the help of a trained technician for repairing the leak and refilling the refrigerant.

4. Malfunctioning of the Compressor

If you find your air conditioner losing the capacity of cooling, it might be because of a faulty compressor. As the name suggests, the function of a compressor is to compress. An air conditioner cannot work without a compressor.

If the cause of poor cooling is a faulty compressor then there is nothing that you can do yourself. You will have to take the help of AC technician. Depending upon the gravity of the damage, the compressor may be repaired or you may have to buy a new compressor.

5. Thermostat Breakdown

A thermostat is a very important part of all devices which are used for cooling or heating. In an air conditioner, a thermostat senses the room temperature and switches on/off the compressor when the room temperature goes below or above the set temperature. If the thermostat is not working properly then the AC may not cool properly or may cool continuously.

This is something that may be difficult to find out yourself so you will have to take the help of a trained AC technician.

6. Outside Temperature is Very High

When the outside temperature tends to rise up considerably, the cooling efficiency of your AC will go down. In high outside temperature, the air conditioner has to work harder so that the outside temperature is lower as compared to the heat which is being released from the air conditioner. The problem becomes more severe for people living on the top floor because the room temperature becomes quite high and it takes longer to cool.

High Outside Temperature
High Room Temperature Impacts AC’s Cooling

High ambient temperature not only affects the cooling but it also means higher electricity bills because the air conditioner has to work extra hard.
If you are living in an area that experiences very high temperatures during summers then you should –

  • Try to bring down the room temperature by reducing the impact of direct sunlight.
  • Make sure there is some shade over the AC unit.
  • Keep doors and windows closed when the AC is on.
  • Keep lights turned off unless required.

7. Under Capacity Air Conditioner

If the room is bigger and the AC capacity is lower, then this will result in poor cooling. That is why we always recommend selecting the right tonnage according to the room size. The below image gives you a rough idea of the AC capacity according to different room sizes.

AC Capacity According to Room Size
Select Correct Tonnage According to Room Size

If you feel you are using an under capacity air conditioner then you may need to upgrade to a higher capacity air conditioner or install an extra air conditioner.

8. Room is Not Properly Enclosed

If the area, which you are trying to cool, is not properly enclosed, it will not be cooled. Make sure that the room, where the air conditioner is running, has its doors and windows properly closed.

Keep Doors Closed
Keep Doors & Windows Tightly Shut When AC is ON

If the doors, windows and other openings like the ventilators are not closed properly, it can cause the cool air to escape, thereby resulting in improper cooling. This will also increase the power consumption of your air conditioner.

You may like to read: 9 Easy Tips for Reducing Power Consumption of Air Conditioners

9. AC is Working in the Incorrect Mode

If you set the AC in the wrong mode, there is no point whining about the device not working properly. Different kinds of weather conditions call for the air conditioner to be running on different kinds of modes to provide accurate results. Therefore, it is important that you set your air conditioner in the right mode. You can learn more about different AC modes and their impact on cooling here.

Incorrect AC Mode
Make Sure the AC is Working in the Correct Mode


Air conditioners are no longer considered to be an item of luxury. They are a major necessity. How relaxing is it to get back home after spending a rough summer day at work and putting the air conditioner at full blast! Even the slightest malfunctioning of the air conditioner can turn out to be extremely worrisome.

Common issues like dirty filters and coils, incorrect mode, windows/doors not closed properly, can be resolved on your own. If the reason for poor cooling is a refrigerant leak, breakdown of thermostat or compressor or any other major technical issue, then you should seek the assistance of a professional.

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Buying Made Easy. Mr10 India