10 possible reasons behind AC not cooling properly

AC not cooling?

Is your AC not cooling properly? It is really irritating when there is an AC malfunction in the horrible summer heat. But then, you can always get an air conditioning repair. However, you also need to understand why your AC is not cooling.

Reasons for AC not cooling

Following can be the possible reasons behind your AC not working properly:(source)

Power problems

This may sound basic to you. But it can be one of the reasons that your AC is not working. You can check once to ensure if the AC is plugged into the outlet correctly or not. Make sure that the power chord is intact.

If the outlet and cord are fine, there can be an issue with your electrical panel. Your unit might have blown a fuse. Many units have overload switches built in. Make sure you check this as well.

Dirty compressor

You should always ensure regular cleaning of the area around the compressor of your air conditioner. Dirt and debris may stop the unit from running properly. You can get your compressor cleaned in such cases. Make sure that your AC gets proper cleaning and maintenance.

Clogged filter

Now, many AC units have a built in mechanism that can shut the unit down if the filter is clogged.

This prevents damage to the heater and also stops overheating. So, maybe your AC filter is too clogged that it is not allowing adequate airflow. Make sure that you check your ac filter. Clean or replace it if required.

Clogged drain

Most of the air conditioners remove moisture from the air by draining out the water through a drain pipe. Now, one of the reasons that your AC is not working can be the clogging of the drain pipe.

Maybe, the pipe is clogged with algae and that is causing the unit to shut down. Well, in that case you can get the pipe cleaned with a mild bleach solution. You can also get the piping replaced if necessary.

Thermostat issue – AC running but not cooling home?

Is your AC not cooling properly? Are you thinking ‘why is my AC not cooling’? Worrying about your AC low cooling problem? Well, maybe the thermostat on your unit is not set at an appropriate temperature. Check your thermostat settings. Maybe the thermostat is broken and has become non responsive.

Try to turn down the dial or push the buttons to the lowest setting. Check if that sets the unit to run. If possible, ensure that all wiring into the thermostat unit is connected properly.

Insufficient cooling gas in AC? – problem of refrigerant leaks

Are you searching ‘ why is my AC running but not cooling’ on the internet? Wondering how to increase AC cooling in home? One of the most common reasons for bad cooling of air conditioners can be a refrigerant leak. Refrigerant levels can drop over time due to slow leaks. When the refrigerant circulation is not sufficient around the evaporator coil, it decreases the efficiency of your AC.

Is your AC not cooling? Well, a refrigerant leak can be the reason behind it. In that case, you can get it repaired as soon as possible. Don’t try to fix the issue yourself as it is a very complex method and requires expertise. If you get these issues fixed, you will be able to experience maximum cooling temperature in AC.

‘WHY AC IS NOT COOLING? – Some common technical problems

daikin ac not cooling
Image source – letcoolaircon

Is your AC not cooling effectively? Are you searching ‘why is my AC not cooling’ online? Have you ever thought about how to increase AC cooling in home? Well, we can help you do that. First, you need to identify the problem properly. (source)

1. Airflow switch

Some air conditioners have safety float switches in them. Now, sometimes the drain pipe backs up with water and this causes those switches to trip. This causes the unit to shut off.

In such a situation, you can reset the switch after the condenser drain pipe is cleaned.

2. Ice buildup

Now, there can be a couple of reasons for the ice buildup in your AC. It can be due to a dirty air filter or a lack of refrigerant. Try to run the unit with just the fan in order to melt the ice buildup.

3. Fix Faulty motor

The cooling ability of your AC might be affected if the outdoor unit is unable to dissipate heat. This can happen if the motor of the fan is broken or faulty.

Sometimes, due to inactivity, dirt or rust makes it difficult for the fan blades to rotate. You can attempt to manually start the motor a few times. Maybe , it will start working.

4. Insufficient coolant

The main function of the coolant is to cool the air flowing over the evaporator coil and spread cool air in the room.

When the level of the coolant is insufficient, the AC fails to cool. But there is always a solution to all your problems. You can get a coolant refill for your AC.

5. Fan problems – Problem in AC cooling system

  • Now, there is a fan in your air conditioner that blows indoor air over your unit’s evaporator coil to cool the air.
  • There is another fan that blows air over the outdoor unit’s condenser to expel heat outside the building.
  • It can be a possibility that either of the fans is not working properly.
  • Faulty motor, lack of lubrication or too much dirt might be the reasons behind the fan issue.
  • So, fan problems can also stop your air conditioner from cooling properly.
  • If you neglect this fan problem, it can lead to compressor failure.

6. Leaking ducts – Reason for low AC cooling

  • The ducts that run through your walls or ceilings carry the cool air from the air conditioner.
  • Maybe , the ducts are broken or have holes in them.
  • This can also be one of the reasons that your AC is not cooling properly.

7. Frozen evaporator coils- reason behind AC running but not cooling house

  • There is a possibility that your air conditioner’s evaporator coil is filled with refrigerant and absorbs heat from the air.
  • Now, these evaporator coils need warm air around them to work properly.
  • If something goes wrong with the airflow, the evaporator coil gets too cold. A layer of ice builds up on the outside.
  • Due to this, your air conditioner may not work properly.

8. Defective capacitors- Causes of AC not cooling

  • Capacitors are very important for the proper functioning of your air conditioners.
  • They are responsible for the working of the motor.
  • The start capacitor sends a jolt to start the motor while the run capacitor provides a series of jolts so that the motor keeps working.
  • So, maybe, either of the capacitors has burnt. This may be the reason behind your air conditioner not cooling properly.

You can get your AC capacitors checked. You can get them repaired or replaced.

9. Worn contactors

  • There are several contactors for the compressor, blower motor and condenser fan motor in all AC units.
  • They make an electrical connection that starts the compressor and motor.
  • Maybe, there are holes in the contactors that are preventing the electrical current to start the motors.
  • This can be a possible reason that your AC is not cooling properly.

AC not cooling properly? Here are some non-technical reasons for the same

Is your AC not cooling properly? Now, there are various reasons that your AC is not cooling properly. Some of them are technical reasons while some are non-technical. Following are some of the reasons given below:

1. Dirty coils – Reason for AC not cooling

  • Sometimes, the condenser coils get dirty and loaded with debris. The condenser is,basically, like a radiator that dissipates heat. In order to dissipate heat properly, the condenser coil must be clean.
  • When the coil gets dirty, the air conditioning system becomes less efficient. Sometimes, the coil is so dirty that the unit is not able to cool the air at all.

2. High atmospheric temperature

  • -Any AC has an optimum operating or surrounding temperature at which it works effectively.
  • -If the temperature gets beyond that desired temperature, then the efficiency of the air conditioner decreases.
  • -Sometimes, the temperature outside is so hot that the compressor of the air conditioner stops working completely.

3. Undersized AC

The size of the AC can also be one of the possible reasons that your air conditioner is not working properly.

Sometimes, the size of the air conditioner is too small when compared to the size of the room.

A small AC in a huge room might find it hard to cool the room when the temperature outside is too hot.

Therefore, always make sure that the size of your AC is according to the size of your room.

4. Faulty remote

  • A dysfunctional remote can also be the cause that your AC is not cooling.
  • Maybe, your AC remote is failing at sending temperature change signals to the AC unit.
  • A simple replacement of the AC remote can solve your problem.

5. Defective parts

Your air conditioner might be having a defective control board, faulty motor, blocked capillary or a faulty run capacitor. These can be the reasons behind your AC not cooling properly.

Ac cooling problem

hitachi ac not cooling
Image source – Kimi Clean

When the summer season comes along, you want your air conditioning system to work without any difficulty. But is your AC unit giving you a difficult time? AC not cooling at all? Wondering how to check AC cooling? Have you identified the problem yet? We can help you identify the problem behind the cooling issue of your AC. Given below is a list of possible problems: (source)

Irregular maintenance

If you want a long life for your AC, you have to make sure that it is periodically maintained. This will ensure optimal function of your AC unit.

Regular maintenance ensures that there is no technical trouble such as refrigerant leakages, compressor damage or coil faults. Maybe, your AC is facing one of these troubles due to irregular maintenance. This might be one the reasons behind the cooling problem of your AC.

Improper placement of AC units

Inappropriate placement of your AC unit may also be the reason behind the malfunctioning of your AC. The indoor and outdoor units of your split AC must be correctly placed for proper functioning. Itn the case of the indoor unit, you have to make sure that the size of the unit is proportional to your room. This ensures effective cooling. An AC unit designed for a medium sized room cannot effectively cool a large room.

Also, your indoor unit should not be over heat sources or windows. This is because they will act as sources of humid air and prevent the effective cooling of your air conditioner. For the outdoor unit, you must ensure that it is kept away from direct sunlight. This is because an increase in temperature can cause the compressor to overheat. A faulty compressor can lead to the malfunctioning of your AC. This can prevent the AC from cooling your home.

Improper heat insulation

Make sure that your room is free of unnecessary sources of heat. Windows that are exposed to direct sunlight should be covered. If there is not proper heat insulation, your AC may not cool the room properly.

Excess ventilation in rooms

Make sure that there is no area in your room that is exposed to direct sunlight. Your room should be properly sealed off in order to ensure effective cooling of your AC unit.

Unclean air filters

Check if the air filters of your AC are clean or not. Sometimes, dirt or debris accumulates on them and restricts the air flowing. This can also result in the inability of the AC to cool your room.

Some Quick solutions for AC cooling problem

Is your ac not cooling properly? Well, keep your worries at bay. We have a list of easy solutions for your AC problems. (source)

  • Repair refrigerant leak There is a quick method through which you can repair your leak. You can get a repair kit for small leaks within the system. You can consult professionals for major leaks.
  • Motor problem Try to kickstart the motor a few times. Sometimes, dust accumulates on the fans and prevents it from functioning properly. Try cleaning the blades of the fan once.
  • Cooling gas issue Maybe there is insufficient gas in your air conditioner. Try to get your coolant gas refilled by a professional.
  • Dirty coils You can clean the dirt and dust that is settled on the evaporator coils. This ensures efficient working of the AC.


Mentioned above is the detailed list of problems that can cause problems to your air conditioner. You can always have an AC repair if you face such issues in your air conditioning system. We hope that our guide on AC problems will help you identify the issue with your AC.


Why my AC is not cooling?

There can be a couple of reasons behind it. There can be a problem in the thermostat settings or there can be a refrigerant leak in your AC. Or maybe, the dirty air filters are preventing the AC from cooling.

Why is AC not cooling enough?

Irregular maintenance of the AC can cause cooling problems. Sometimes, dirt accumulates on the condenser coils which can block proper air flowing. Cleaning of the coils can help in the proper cooling of AC.

What causes the air conditioner not to work?

There can be a lack of power or a thermostat issue causing the AC malfunction. A frozen coil might also be the reason. You can get the help of a professional for identifying the real problem.

How do I know if my AC fuse is blown?

You can check the fuse wire. If you see a gap in the wire, then the fuse is blown and should be replaced.

Why is AC running but not cooling the house?

There may be an issue with the compressor or refrigerant. The air condenser may also be dirty and blocked. 

1 thought on “10 possible reasons behind AC not cooling properly”

  1. Hey,
    It is really a displeasing situation in summer heat when there is an AC malfunction. Every common problem which can cause AC malfunction is mentioned and with that amazing AC repair tips are also given. Useful tips!

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