AC not Blowing Cold Air but Running.

AC not Blowing Cold Air but Running? Find Out Why and Fix it.

There exist various potential causes for AC not Blowing Cold Air but Running, these ranges from thermostat malfunctions, compressor issues, and evaporator coil problems to a straightforward obstruction by dust and debris, all of which can hinder its proper operation.

Quick Insight: AC not Blowing Cold Air but Running due to Thermostat Issues,Frozen Evaporator Coil,Clogged Air Filter,AC is More Than 15 Years Old or Outdoor Unit is Dirty,

Also read>>>>Ac Running But Not Cooling.

Why AC not Blowing Cold Air but Running.

1.Thermostat Issues.

When your AC not Blowing Cold Air but Running, one of the initial culprits to investigate is the thermostat. There are a few potential problems related to the thermostat:

Improper Settings: Check if your thermostat is turned on and set to the ‘cool’ mode. Sometimes, it might accidentally be set to ‘heat’ or a different mode.

Fix: Ensure your thermostat is set to ‘cool.’ To test its functionality, lower the temperature setting a few degrees below the current room temperature. If the air conditioning system kicks in and you start feeling cooler air, the issue is likely resolved.

Calibration Issues: Incorrect calibration of the thermostat can lead to an absence of cool air. This means that the temperature it reads does not accurately reflect the room temperature.

Fix: If you suspect calibration issues, consult your thermostat’s manual for instructions on recalibrating it. This typically involves a simple adjustment to align it with the actual room temperature.

Wiring Problems: Sometimes, the wiring connected to the thermostat can become damaged or disconnected, leading to incorrect temperature readings and issues with your AC.

Fix: If you suspect wiring problems, it’s best to contact a professional HVAC technician to inspect and repair the wiring. Attempting to fix the wiring yourself can lead to more problems if not done correctly.

Tips: To ensure efficient cooling, make sure that your windows and doors are closed to prevent warm air from entering your home and that your vents are open and unobstructed to allow proper airflow through the system.

Also read>>>Air Conditioner Is Squeaking .

2.You Have a Frozen Evaporator Coil.

One of the frequent reasons for your air conditioner running without providing cool air is the occurrence of a frozen evaporator coil. This occurs when the evaporator coils become encased in ice, obstructing proper airflow and hindering the cooling process. Several factors can contribute to this issue, including:

  • Dirty Air Filters: Clogged or dirty air filters restrict the flow of air over the evaporator coils, causing them to become excessively cold and freeze.
  • Malfunctioning Fan: A malfunction in the fan that circulates air over the evaporator coils can result in insufficient airflow, leading to coil freezing.
  • Refrigerant Leak: A refrigerant leak can disrupt the balance of the cooling process, causing the evaporator coils to freeze due to irregular temperature and pressure conditions.


Resolving a frozen evaporator coil is best left to HVAC professionals due to the complexity of the issue. Here’s how it can be addressed:

  • Professional Inspection: Contact a qualified HVAC technician to examine the frozen evaporator coil and determine the root cause.
  • Thawing: The technician will initiate the thawing process to remove the ice buildup from the coils.
  • Addressing Underlying Issues: Depending on the cause, the technician will take appropriate measures to address the underlying issue. This might involve replacing dirty air filters, repairing or replacing a malfunctioning fan, or fixing any refrigerant leaks.
  • Coil Replacement: If the evaporator coils are damaged or have a refrigerant leak, they may need to be replaced to restore the AC’s proper functioning.

3.You Have a Clogged Air Filter.

A common issue that many homeowners encounter when their air conditioner is running but not cooling is a clogged air filter. An excessively dirty or clogged filter can impede airflow, resulting in reduced cooling efficiency. It’s important to note that even if your air filter is located within your furnace’s blower, it can still have a significant impact on the overall cooling process.


Addressing a clogged air filter is a relatively simple task that can significantly improve your air conditioner’s performance:

  • Regular Inspection: You should make it a habit to inspect your air filter on a monthly basis. Look for signs of dirt, dust, or clogs.
  • Cleaning or Replacement: If you notice that the filter is dirty, clogged, or reaching the end of its lifespan, you should clean or replace it as needed. Be sure to follow the manufacturer’s instructions regarding maintenance and replacement intervals.
  • Increased Frequency for Special Situations: If you have pets in your home or someone with allergies, you may need to change the filters more frequently, as these conditions can lead to faster filter contamination.
  • Professional Assistance: If cleaning or replacing the air filter does not resolve the issue and your air conditioner is still not cooling properly, it may indicate a more significant problem beyond the filter. In such cases, it’s advisable to seek the expertise of a professional HVAC technician who can identify and address any underlying issues with the cooling system.
  • You May Have a Tripped Breaker

When your air conditioner isn’t running at all, it may be due to a tripped circuit breaker. This can result in a lack of power supply to your AC unit, preventing it from cooling your home effectively.

Also read>>>AC Fan Not Spinning.


Addressing a tripped breaker is a straightforward process that can help restore power to your AC system:

  • Check the Circuit Breaker: Begin by checking your home’s circuit breaker panel. Look for the circuit breakers that are dedicated to your air conditioning system. They should be labeled, indicating their purpose.
  • Reset the Breaker: If you find that the breaker is in the “off” position, flip it to the “off” position and then back to the “on” position. This action can reset the breaker and restore power to your AC unit.
  • Test the AC: After resetting the breaker, check if your air conditioner starts running and cooling your home. If it does, you have successfully resolved the issue, and your AC should be functioning correctly.
  • Additional Issues: If resetting the breaker does not resolve the problem and your air conditioner still doesn’t work, there may be other underlying issues. In such cases, it’s recommended to seek the assistance of a professional HVAC technician to diagnose and repair the problem.

4.Your AC is More Than 15 Years Old.

If your air conditioner is more than 15 years old, it may be the cause of reduced cooling effectiveness. Older AC units tend to be less efficient than newer models, and their performance can diminish over time.


Dealing with an aging AC unit that’s no longer effectively cooling your home involves considering an upgrade to a new and more efficient system:

  • Assessment: Begin by assessing the age of your AC unit. If it’s over 15 years old and hasn’t received significant upgrades or parts replacements, it’s a good indication that it’s nearing the end of its efficient lifespan.
  • Consultation: Contact an HVAC professional to evaluate your current AC system and provide recommendations for a replacement. They can help you determine the appropriate size and type of new AC system that will suit your cooling needs.
  • Upgrade: Consider investing in a new and improved air conditioning system. Newer models are designed to be more energy-efficient and capable of keeping your home cool while minimizing energy waste.
  • Professional Installation: Have your new AC unit professionally installed to ensure it operates at peak efficiency and provides optimal cooling performance.

Upgrading to a modern AC system is a prudent choice when dealing with an aging unit. It not only enhances cooling efficiency but also contributes to energy savings, making your home more comfortable during the summer months while being environmentally friendly.

Also read>>>>Air Conditioner Hissing.

5.Your Outdoor Unit is Dirty.

An air conditioner that is running but not providing cool air may be a result of an outdoor unit that has accumulated dirt and debris.

The outdoor unit, or condenser, is responsible for heat exchange and is exposed to the elements. Over time, dirt and dust can build up on the unit, potentially obstructing airflow essential for efficient cooling.


Addressing a dirty outdoor unit requires professional expertise and care:

Professional Cleaning: It is advisable not to attempt cleaning the outdoor unit yourself. Contact a professional HVAC technician to assess the extent of dirt and debris buildup and clean the condenser properly.

Prevention and Maintenance:

To prevent this issue and maintain optimal AC performance, you can follow these preventive measures:

  • Clear Surroundings: Ensure the area around your outdoor unit is free from bushes, trees, and any obstructions. This will allow for better airflow and reduce the accumulation of debris.
  • Condenser Fins Maintenance: Carefully clean the condenser fins on the outdoor unit. Gently remove any visible dirt or debris from the fins to maintain efficient heat exchange.
  • Regular Washing: Periodically wash the condenser with soap and water to remove accumulated dirt and grime. Be sure to turn off the power to the unit before cleaning.
  • Off-Season Covering: When your AC is not in use during the off-season, securely cover the condenser. This prevents dust and debris from accumulating during periods of inactivity.

Household Air Filtration: If your home has excessive dirt and dust issues, you can invest in an air filtration system to help maintain cleaner indoor air quality and protect your household.

Also read>>>AC Unit Blowing Hot Air Outside.

Frequently Asked Questions (FAQs)

Why is my AC not Blowing Cold Air but Running my home effectively?

There could be various reasons for this issue. Common causes include thermostat issues, a frozen evaporator coil, a clogged air filter, or an aging AC unit. Each of these issues can impede the cooling process, and the appropriate fix depends on the specific problem. It’s advisable to consult an HVAC professional to diagnose and address the issue correctly.

What should I do if my air conditioner’s circuit breaker has tripped, and it’s not cooling my home?

A tripped circuit breaker can indeed lead to your AC not running. To fix this, locate your AC breaker in your electrical panel, reset it by flipping the switch from “off” to “on.” If this resolves the problem, your AC should start running again. However, if the issue persists, consider seeking professional assistance, as there may be other underlying problems.

How can I prevent my outdoor AC unit from getting dirty and affecting its performance?

To maintain your outdoor unit and ensure it operates efficiently, follow these preventive measures:

  • Clear the area around the unit from bushes and trees to allow proper airflow.
  • Periodically clean the condenser fins and wash the condenser with soap and water to remove accumulated dirt.
  • When your AC is not in use during the off-season, securely cover the condenser.
  • Consider investing in an air filtration system if your home has excessive dirt and dust issues.

Is it normal for an air conditioner to lose efficiency after 15 years?

Older AC units can indeed become less efficient over time. If your air conditioner is more than 15 years old and hasn’t received significant upgrades or parts replacements, it may not cool your home effectively. Consider consulting an HVAC professional to evaluate your unit and discuss the benefits of upgrading to a new, more efficient system for better cooling and energy savings.

Also read>>>Air Conditioner Not Working After Power Outage.


When your AC not Blowing Cold Air but Running, there are several potential causes to consider. These include issues with the thermostat, a frozen evaporator coil, a clogged air filter, an aging AC unit, or even a tripped circuit breaker.

Addressing these problems may require different solutions, from simple thermostat adjustments and filter maintenance to professional assistance for more complex issues.

Additionally, proactive maintenance measures, such as keeping the outdoor unit clean and unobstructed, can help prevent cooling problems.

Regular HVAC maintenance and, when necessary, upgrading to a more efficient system are key steps to ensure consistent, reliable, and efficient cooling in your home.