Top 6 Reasons Why Your AC is Running but Not Cooling

Person using a remote control to set an air conditioner to 19 degrees celsius.



Your air conditioning system may cease cooling your home for various reasons, which may be technical and others that aren’t. To better understand its malfunction, these are the most typical factors why your AC is not cooling properly.


  • Broken Thermostat
  • Is my thermostat really broken?
  • When to know if my thermostat settings are bad?
  • Dirty/Clogged Air Filter
  • How often should I clean my air filter?
  • AC Condenser is Blocked
  • Where is the optimal location for an AC condenser?
  • Bad/Broken AC Compressor
  • Fan Motor is Broken
  • Tripped Circuit Breaker
  • Key Takeaway


Broken Thermostat

A thermostat malfunction is a common problem yet difficult to detect.

It is crucial to check your thermostat regularly to see if it’s working properly or not.

What a thermostat does is that it detects the temperature in the room and signals the compressor when to begin or stop the cooling cycle. If the thermostat fails, the air conditioner may start having a cooling problem.


Is my thermostat really broken?

It’s a little worrisome when your thermostat quits working, especially when the weather outside makes it exceedingly uncomfortable inside that you need an air conditioner right away.

What are the signs that your thermostat is malfunctioning? To discover why anything is wrong with your air conditioner, these are the usual indicators of a broken thermostat.

The thermostat display is blank.

It is obviously problematic if your thermostat is not turning on. If your digital thermostat becomes unresponsive and displays just a black screen, you should have it inspected by a professional.

Your air conditioner or heater won’t turn off and is always running.

If your heating/cooling system constantly runs without shutting off, there is certainly a problem. In this situation, it’s possible that there is a wiring defect or that the thermostat isn’t properly calibrated.

The room temperature and the thermostat setting are incompatible.

When room temperatures do not match, this is a common indicator of a broken thermostat.

Temperature fluctuations across rooms are normal in a zoned home. If your home isn’t zoned, temperature fluctuations in different rooms could indicate a broken thermostat.

The thermostat is the ideal spot to begin troubleshooting. Replacing your thermostat is a simple, quick, and inexpensive approach to solving the problem.

When to know if my thermostat settings are bad?

Ensuring that the thermostat is in the right setting is always important.

If you have a non-programmable thermostat, make sure it is set to AUTO mode.

During the winter, set your thermostat on HEAT, and in the summer, set it to COOL.

If your air conditioner or heater is always running, your thermostat may be set to “ON,” allowing the HVAC system to run and blow air through vents even when the air isn’t cooled or heated. Set the settings to “AUTO” so that the system only operates when the air is actively cooling or heating.

Dirty/Clogged Air Filter

Another reason the air conditioner does not cool is a clogged air filter.

If the air conditioner filter is dirty or clogged with dust and grime, it can cause various issues that can affect the AC’s performance. In this circumstance, air cannot flow freely, significantly reducing the air conditioner’s cooling capability.

It may also cause the evaporator coil to freeze, preventing cool air from exiting the system. To avoid such problems, clean or replace the air filter as necessary.


How often should I clean my air filter?

To ensure that your air conditioner is cooling properly, cleaning your air conditioner’s filters is the most crucial maintenance chore.

Filters clogged with dust and dirt reduce a system’s efficiency and result in higher electricity bills. Your air conditioner’s energy consumption can be lowered by 15% by replacing a clogged filter with a new, clean one.

Cleaning the air conditioner filters every two weeks is a good rule of thumb. However, it would be best to clean filters in dusty or dirty environments more often.

AC Condenser is Blocked

The condenser is an important component of an HVAC system because it converts the hot refrigerant into a cool substance after compression.

If the condenser becomes clogged with dust and debris, the amount of cooling provided by your air conditioner reduces, and the system’s functionality suffers. It makes it difficult for the cooling system to remove heat and cool your home.

In addition, a blocked AC condenser coil reduces your air conditioner’s efficiency. Thus, your air conditioner will take longer to cool a space, resulting in higher power expenditures.


Where is the optimal location for an AC condenser?

The best location for an air conditioner condenser is outside your home. It should always be located outside, where it will not receive much sunlight and has unrestricted access to fresh air.

Placing a condenser unit indoors, such as in a garage, reduces the air supply to your system, which limits the amount of heat it can eliminate from your home.

Bad/Broken AC Compressor

The compressor is the component that causes your air conditioner to operate. If it fails, no refrigerant is circulated, which means the system produces no cool air. Compressors frequently fail as a result of prolonged use without regular maintenance.


Simple cleaning will not always suffice because the condenser may require replacement, especially if broken. A condenser can be damaged by debris and other materials, and if this is the case, only a replacement is the key to having your AC working again.


Fan Motor is Broken

The fan motor is a simple but critical component of an air conditioner. It is the component of the unit that circulates air throughout the system.

If the fan motor starts to fail, the outdoor unit’s fan will be unable to generate heat, resulting in the AC failing to cool your home.


Since the fan motor is one of the most heavily used parts of an air conditioner, it needs to be repaired or replaced regularly. However, you should budget for the expense of replacement, including labor, as it might be costly.


If the AC fan motor or capacitor is broken, you should always get them repaired or replaced by a professional HVAC technician.


Tripped Circuit Breaker

AC tripping can be caused by various issues, which may or may not be seasonally linked. These issues may cause your air conditioner to use more energy during the summer or be less efficient.


When this occurs, reset it and wait an hour to see if your air conditioner begins to chill your home. If the breaker does not trip again, you can resume normal air conditioning operation. However, if the breaker trips again, it suggests your air conditioner, electrical system, or both are malfunctioning.


When this happens, please do not attempt to flip it again. Simply contact a professional to identify and resolve the issue.


Key Takeaway

Nothing is worse than a broken air conditioner on a hot summer day. This article has taught us several reasons why an air conditioner isn’t cooling our home.

From checking the thermostat and its settings to changing the filter, you can get your air conditioner running again on your own. However, if you’ve done all of the air conditioner troubleshooting and remedies and it’s still not functioning, you might need professional help.


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