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Why is the Air Conditioning Not Cooling? | Frequent Causes

It is a common experience for air conditioning units to stop cooling the room, and when this happens, you find yourself sweating through the night, and then face the same ordeal through the hot afternoons. Unfortunately, most times, you only get to notice that your unit is not cooling on the hottest day of the summer, and nothing you do will seem to work. For additional resources about air conditioning, please visit our website at

If the cause of the problem is a minor one, you may be able to do some basic troubleshooting and solve the problem. However, this will not always be the case, as the service of a professional HVAC contractor will be required to fix the system.

In this article, we address the frequent causes of your air conditioning not cooling. 

Why is the ac not blowing cold air?

There are many reasons why your AC unit is not cooling. The following are some of the common causes of this problem:

Improper Installation 

You may find that the air ducts of your AC unit are leaking if the system was not properly installed from the start. The implication of this is that the leaky ducks will allow more dust into the system and prevent the home from cooling.

The first thing you can do in this situation is to check for tears in the ducts. Using duct tape to seal the tears could work, but it should be seen as a temporary solution. Also, confirm that the joints that connect the air ducts are properly sealed. 

If you cannot identify or seal the leak, the next thing to do is to call a licensed HVAC contractor.

The thermostat is set incorrectly

Your thermostat does the work of sensing the temperature of the room and tells the compressor whether to begin or end the cooling cycle. If there is a problem with your thermostat, your air conditioner may stop cooling or continue cooling without stopping.

The first thing you may want to check when you notice that the temperature of your home is getting higher than normal is the thermostat settings. Even if you’re sure that you have set the thermostat to cool, you should check again to be sure that it hasn’t been changed to heat or constant fan by someone else.

If the AC is still not cooling after some minutes that you have confirmed the thermostat settings, it may be time to check some other parts of the unit.

The air filter is clogged

If you find that there is nothing wrong with your thermostat and the air inside your home is still not cool, your air filter may be the culprit.

The main function of the air filter of your AC unit is to ensure that dust, dirt, and other airborne particles do not find their way into the system. This keeps the system’s components inside clean and functioning more efficiently. 

When the air filter is clogged, the airflow is affected, thereby reducing the cooling of the home. In extreme cases, a dirty or clogged air filter can cause the AC unit to shut down completely.

What you need to do is to turn the system off, locate and remove the air filter, and then inspect it for dirt or debris. If your AC unit still fails to cool your home even after the clogged air filter is cleaned, then you will have to do more to locate the source of the problem.

The compressor is faulty

The compressor is said to be the heart of the air condition system which ensures that the room is kept cool. Therefore, a defective compressor may also cause your air conditioning system to stop cooling. 

It does its work by compressing the refrigerant and circulating it through the condenser and evaporator coils. Once the compressor malfunctions, the cooling cycle fails to start, and the AC stops cooling.

If you notice that your compressor is failing, then it’s time to call a professional to get it fixed.

The condenser is blocked

The condenser works like a radiator that dissipates the heat that was removed from the home. If the condenser coils are loaded with dirt or debris, they can start manifesting in the air conditioning unit. When functioning properly, the fan of the condenser pulls air into the exterior unit through the condenser coil. This is done to pull heat energy out of your home.

The condenser has a large outdoor coil that encapsulates most of the exterior part of the air conditioning unit. This large coil has some thin metals known as fins which are spaced in a well-coordinated tightness. When operating correctly, the condenser fan draws air into the outdoor unit through the condenser coil to pull heat energy out of your home.

Sometimes, these fins can start to collect dirt and debris, thereby clogging the coil. This could cause the efficiency of the condenser to drop, thereby making it work harder to make the room cool. The implication of this is that your AC unit will never be cold enough to make the room cool.

If you notice that the coil has accumulated dirt, you can use a brush attachment to clean it or rinse it gently with a hose. If the problem persists after this, you will have to contact a professional to get your AC unit fixed.

Refrigerant leak

When the refrigerant leaks to a certain degree, your AC unit may stop to blow cool air, or fail to adequately cool your home even after running for a long period. It can also cause your compressor to fail and shut your AC unit down completely.

Checking and resolving issues involving refrigerant levels in your system is another job for your local Carrier dealer. 

To resolve issues relating to your refrigerant, you will need to engage the service of a professional. You can get reviews on different AC repair companies on Better Business Bureau.

Bottom Line

Your AC unit can develop problems with time, and the cause can be traced to many different things. The best way to address most of these issues is to call a qualified HVAC contractor. They will help you assess your AC unit, trace the cause of the problem, and recommend the best solution to the problem.

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