Outside AC Unit Running But No Air Blowing Inside | 9 Reasons & How To Fix

Outside AC Unit Running But No Air Blowing Inside

It can be frustrating when no air is blowing inside your home, yet the AC unit is running. An AC that is not cooling or blowing adequate cold air is the last thing you want in your home, especially during summer.

AC malfunctioning is a common issue, but it’s no fun having a sleepless night due to the heat. Therefore, it is vital to identify why your air conditioner is not functioning normally.

The following is a list of reasons behind AC not working and ways to fix them:

1 – Dirty Coils

One of the common reasons your AC is malfunctioning is dirty coils. If the condenser or evaporator coil is filled with dirt, the air conditioner may not be able to absorb excess heat from your home and blow cold air into your room.

Dirt and other debris significantly affect the ability of the AC to cool your home. The efficiency of the AC is considerably reduced, and the coils are unable to do their work properly.

Therefore, you need to fix dirty coils as soon as possible to increase the efficiency of the condenser and the evaporator.

You can fix the issue of dirty coils by removing dirt and other debris from the condenser. Ensure that the outside unit (condenser) is clean through regular maintenance and repair.

2 – Dirty Air Filter

When your AC is malfunctioning, the first thing to check is whether your air filters are clogged. Dirt and dust restrict air from blowing into your house. Thus, the cooling ability of the AC is limited and is unable to blow adequate air into your room.

Clogged air filters may also hamper the thermostat from functioning correctly. This is because they block the movement of cool air into the AC ducts.

However, this should not distress you. The problem can be easily fixed by replacing unclean air filters with new ones. Ask a professional how often you need to change your air filter.

3 – Faulty Motors

You may be troubled why your AC is still not working after replacing the air filters and cleaning the evaporator and condenser coils. However, have you checked if the AC motor is functioning efficiently? The motor may be faulty, and that is why your AC is not cooling your house efficiently.

Thus, you need to check the operation of the AC motors. A faulty or broken motor prevents the air conditioner from dissipating heat, hence preventing the outside unit from cooling your home.

Fixing a faulty or broken motor is not easy unless you are a professional. Hence, homeowners and other AC users are encouraged to call or hire a professional.

4 – Defective Thermostat

If the air blown into your room is insufficient, you can check the working capacity of the thermostat. A faulty thermostat makes it hard for the air conditioner to transfer cold air into your home.

The function of a thermostat is to notify the compressor to halt or initiate the cooling process. It does this by first sensing the room temperature.

Incorrect settings of your thermostat may also be the reason outside AC is not effective in dissipating heat from your house.

A thermostat can be fixed by repairing it or replacing it with a new one. Therefore, calling or hiring a professional to do the work for you is essential. Unless you are sure of what you are doing, do not attempt to repair a thermostat because you may damage other parts of the air conditioner.

Incorrect thermostat settings can be rectified by changing your thermostat from “On” mode to “Auto” mode. Once you do that, your air conditioner should work fine.

5 – Faulty Compressor

One of the critical parts of an AC is the compressor. It cools your home by managing the circulation or air between the inside unit (evaporator) and the outside unit (condenser).

Thus, a damaged compressor causes the air conditioner to malfunction and fail to remove heat from your room. Also, the cooling process fails to start making the air conditioner ineffective.

Nonetheless, a faulty compressor should not give you sleepless nights. It can be fixed by replacing the damaged compressor with a new one. It is not easy to do this; therefore, you need to call an expert to do the work for you.

AC manufacturers recommend users have their air conditioners maintained and serviced regularly by a professional. This will keep the AC in good working condition and save you from sleepless nights due to heat.

It is advisable to service your AC every three months to improve its output and efficiency. Also, fixing a faulty compressor may be expensive. Thus, regular maintenance can save you from spending your hard-earned money to purchase a new compressor.

Remember, prevention is better than cure.

6 – Inadequate Coolant

The function of the coolant is to cool air and transfer it to your home.

Therefore, AC cannot cool air efficiently when inadequate or a small amount of coolant is in the AC.

This issue can be fixed by refilling and topping up the coolant.

7 – Low or Leaking Refrigerant

The chemical or fluid that controls the entire cooling process is called refrigerant. If your outside AC is running but not air blowing inside, its refrigerant may be low. The fluid is often lost through leaking.

R410A or Puron is the commonly used refrigerant. This fluid is needed by the AC to blow cold air inside your home.

If you notice an ice buildup on the outer part of the AC or hear bubbling or hissing noises, all these are signs of a low refrigerant. You need to hire an expert to fix the issue.

8 – Faulty Parts

Your AC may be unable to blow air inside due to defective parts. This includes a defective motor, choked capillary, and a defective thermistor. You should also check if the control board and capacitor are defective.

Inspect all parts of the AC regularly to identify faulty components. Service and maintain the AC regularly for the best results.

9 – Old Air Conditioner

Old age is associated with losses. When your AC becomes old, it loses its capacity to blow air inside your room.

Just like older people, an old AC loses its power and strength to supply your room with cool air.

This problem can be fixed by purchasing a new AC system and replacing the old one.


I hope you will have the right solution to your malfunctioning AC when you finish reading this article.

If any part of the AC becomes faulty, the ability of the AC to blow air inside your house is reduced considerably.

Consider replacing all the defective parts and refilling your refrigerant if there is a leak. Keep your AC in good condition by servicing and maintaining it regularly.

Do not hesitate to call professionals whenever you are stuck.


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