Why Is My Air Conditioner Running but Not Cooling?

Having your air conditioner running but not cooling during the hot summer can be a nightmare. After all, the heat waves are not easy to cope with during the wild summer days. But before you call an expert for help, it is better to try to see for yourself the root cause of the problem. Most minor issues can be resolved with a little legwork on your part, and if all else fails, you can always turn to professional help.

ac not cool

Read this article to learn some of the most common causes of why this may be happening to your AC unit. Understanding these issues can help you get your AC back on track and keep your home cool in extreme weather. So, you can either read on to know more or call professional AC repair experts to look into the matter!

6 common causes of air conditioners running but not cooling

When your air conditioner is turned on and it’s not cooling the room properly, you need to check specific components of your cooling system to ensure that they are functioning properly.

These components are some of the most common causes for problems with your air conditioner running but not cooling:

  1. Compressor
  2. Condensor
  3. Evaporator
  4. Thermostat
  5. Ductwork

If you notice visible damage or improper performance in any of these AC components, it is best to contact an HVAC expert to resolve the issue.

1. Cleaning and checking for blockages

ac cleaning

If the air conditioner is running but not cooling, you should check for any blockages in the unit. A dirty filter might be preventing your cooling systems from working optimally. Clogged filters can cause your system to work harder, leading to increased energy costs and possible breakdowns.

It’s important to check your filter and replace it as needed. It can be done by removing the filter and inspecting it for any dirt or debris causing a blockage. If there is a blockage, clean it out and replace the filter.

2. Refrigerant leaks

A common cause for your AC unit not cooling is low refrigerant levels. Refrigerant is essential for absorbing heat from indoors and releasing it outdoors. With low refrigerant levels, this process will be less efficient and effective. If there’s a refrigerant leak, there’s not enough refrigerant to do the job. That can make your air conditioner run but not cool properly.

3. Thermostat setting

The next reason your air conditioner is not cooling the room is a thermostat issue. Check your thermostat temperature setting. If you set your thermostat too low, your air conditioner will constantly run to reach the desired temperature, wasting a large amount of energy and eventually wearing it down. You should also ensure that your thermostat is not set to “heat” mode instead of “cool” mode.

4. Incorrect air flow

Incorrect air flow can stop your air conditioner from cooling the room thoroughly. If the airflow is insufficient, it could be due to a clogged air filter, closed vents, or dirty coils. A clogged air filter is one of the most common reasons for reduced airflow. After repeated usage, the air filter often traps dust and dirt particles, which can eventually build up and restrict airflow. Checking your air filter regularly and changing it when necessary is the best way to ensure optimal airflow.

5. Frozen evaporator coils

The evaporator coils are in charge of absorbing heat from the indoor air. So if they’re frozen, naturally, they won’t be able to absorb the heat. As a result, the unit won’t cool the room even if it’s turned on. Therefore one also needs to check the evaporator coils and make sure it’s not packed with ice.

If you suspect that dirty coils are to blame for your frozen evaporator coils, the best course of action is to contact a professional HVAC technician for help. They will be able to clean the coils and get your AC unit back up and running in no time!

6. Ductwork leaking

There are a few reasons why your ductwork could be leaking. One reason could be that the seals around the ductwork are old and need to be replaced. It could be possible that the ductwork was not installed and sealed correctly. Any holes or gaps in ductwork could also cause concern.

If you think your ductwork may be leaking, it’s important to have it inspected by a professional as soon as possible. Leaking ductwork can lead to higher energy bills and decreased indoor air quality.

Why do you need to call a professional HVAC technician to resolve this cooling issue?

professional hvac repair

Your AC is one of the most important appliances in your home, more so during hot summers. Any breakdown can leave you sweating in the heat.

While minor air conditioning system issues can be handled at home, severe air conditioner issues should always be handled by trained professionals. HVAC technicians have the training and experience necessary to diagnose and fix problems with air conditioning units within no time.

Trying to fix severe problems yourself could make the situation worse. So it’s always best to leave it to the experts. Additionally, getting the issue fixed by a professional HVAC technician will help you save in the long run.

Tips to keep your air conditioner maintained

Following are some of the tips to maintain your air conditioner to save you time and money in the long run:

  1. Make sure to keep the area around the outdoor unit clean and clear.
  2. Invest in a programmable thermostat.
  3. An uneven surface can cause the unit to vibrate and make noise. So, it is important to make sure the outside unit is level.
  4. The air filters should be changed every two months at a minimum and more frequently if you have pets or allergies.
  5. Check for any leakage.
  6. Ensure proper ventilation in the room.
  7. Have your air conditioner serviced annually, as regular maintenance is the most important step to ensure the longevity and efficiency of your AC.


As you can see, there are multiple potential causes of the air conditioner running but not cooling. As a responsible homeowner, you need to check every part of the unit frequently to ensure it’s running properly. Issues like refrigerant leaks, frozen evaporators, dirt build-ups in small components of the unit or wrong thermostat settings can cause disruptions in the working of the air conditioner. However, if you need to figure out what’s exactly causing your air conditioner to run but not cool, it’s best to call a qualified technician for diagnosis and repair.

Images by Depositphotos


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