The Most Common Reasons for AC Not Cooling

In the hot summer days, one of the most reliable home appliances is an air conditioner. They are meant to keep the room temperature cool and provide the best possible comfort. However, due to some mechanical or technical errors, your air conditioner may stop providing its services which could affect your overall health and mood.

In such phases, the natural reaction of most AC users is to niggle and call for professional help to troubleshoot the problem which even they could have solved. Yes, you heard it right; most of the issues in an air conditioner are not rocket science and could be sorted out by you.

So, in an attempt to help you learn more about your AC’s problem, more specifically, AC’s cooling problem, we have brought you some common reasons and suggestions that will come in great help. Eventually, by learning these reasons, you would be able to solve most of your AC’s problems and save money that you would otherwise spend on external help.

7 Reasons for AC not Cooling and Solutions

Here are the 7 most common reasons why your air conditioner may not be cooling your room:

  • Incorrect Thermostat Setting
  • Issues with AC Unit placement
  • Dirty Air Filter
  • Unclean Coils
  • Insufficient Refrigerant
  • Improper or Irregular maintenance
  • Faulty AC Components

1. Incorrect Thermostat Setting

When you notice the cooling problem, the first thing that you need to do is to check the thermostat settings. A thermostat is a component that maintains the AC temperature so if you are feeling hot even if your AC is running, your thermostat settings may have been set to ‘ON’, ‘Constant Fan’, or ‘Heat’.

In such settings, your air conditioner unit blows out lukewarm air which could be a problem. Turn the settings back to ‘Auto’, and this should solve the problem.

Solution: Turn the thermostat settings back to ‘Auto Mode’ instead of ‘ON’ mode.

2. Issues with AC Unit placement

Another common reason that may be hindering the cooling is the improper placement of the air conditioner unit. If you have a split AC, you have two major units indoor and outdoor.

It might be possible that your AC cooling capacity is not sufficient enough for the room and that’s the reason you are not experiencing cool air. The indoor AC unit should be placed in a room only after considering the size of the room and cooling capacity of the air conditioner.

In the case of your outdoor unit, the reason for AC not cooling may be due to the AC compressor being exposed to the direct sunlight, or overheating. When a compressor is overheated, it shuts down, and the heat cycle could not be maintained, and this is where you will experience no cooling.

Solution: Make sure the indoor unit of the AC is not undersized, and the outdoor unit is not exposed to direct sunlight or placed in high-temperature surroundings.

3. Dirty Air Filter

The air filter is the most ignored component of the air conditioner, and if you have been doing so, this may be the reason why you are not experiencing cool temperature in your room.

When the air filter gets dirty or clogged the air conditioner components have to work harder to keep up and maintain the desired temperature, this results in overheating and thus no cooling.

For a proper passage of warm air and cold air inside the duct, it is quite important that the air filter is clean and free from any blockage. This will maintain the heat cycle, and cooling will be on point.

Solution: Check the air filter for any clogging. Clean the AC and filter regularly. If necessary, replace the filter.

4. Unclean Coils

If your air conditioner is not cooling, it is quite possible that the AC coils are loaded with dirt and debris. Both evaporator and condenser coils are designed to carry the refrigerant fluid that helps to maintain the heat cycle.

When these coils get clogged, the AC components becomes less efficient and have to work harder to maintain the temperature of the room. Eventually, the components stop functioning, and there is no cooling from the air conditioner.

Solution: Cleaning the AC coils before summers or once in a year is recommended to get immune from the air conditioner cooling problem.

5. Insufficient Refrigerant

One of the most vital items used in an air conditioner is a refrigerant. This is a fluid that absorbs the heat from the room and helps to maintain a proper heat cycle. When the refrigerant is at a low level inside the coils, there is less absorption of heat from the room, resulting in a less cool environment.

The insufficiency of the refrigerant level could be caused due to gas leakage. How do you know when you are low on your refrigerant level? Well, look for the following things:

  • The evaporator coil freezes.
  • There is ice on the refrigerant line.
  • Hissing or bubbling noise in case of heavy leakage.

Solution: The refrigerant fluid is essential in your AC to blow out cool air; one of the biggest reason it would be low in level is due to leakage. Look for a professional technician in such situations.

6. Improper or Irregular maintenance

If you are not receiving cool air from the AC, maybe it is due to poor maintenance. It is advisable that you let a professional technician run a proper check-up on the AC unit once a year.

Problems like clogging in air filters and coils, refrigerant leakage, issues in compressor, evaporator, and condenser could be solved immediately for the best summer experience.

Solution: Improper or irregular maintenance could lead to an underperforming air conditioner and ruin your summers. Once in a year, get a professional technician to analyze the ac unit and solve the issues.

7. Faulty AC Components

Lastly, one of the biggest reasons that obstruct the cooling in your room is due to faulty AC components.

The six most important components of an air conditioner are – evaporator, condenser, compressor, thermostat, blowing unit, and refrigerant. Only one defective component is enough to be the reason for your AC not cooling your room. If any of your AC components are defective, damaged, or broken, you could contact the particular brand for replacement.

Solution: Sooner or later, the components of your air conditioner will get damaged, the best advice is to go for a brand or model that offer a longer warranty period or is well-established in the industry.


There are many reasons why your air conditioner is not cooling your house/room. Some of the most common reasons are – incorrect thermostat settings, dirty air filter, clogged AC coils, improper Ac unit placement, faulty components, insufficient refrigerant, and irregular maintenance.

All the reasons are discussed above in a comprehensive manner. In addition to that, we have given the best possible solutions for each, so that you could make the most out of this article and sort out the majority of your AC related problems. We hope you have learned something valuable from this page. Good Luck!