Why Is My AC Running But Not Cooling My Home?

Few things are more frustrating than an air conditioner running but not cooling the house. You hear the hum and feel the air blowing, but it’s warm, stuffy, and uncomfortable. If you’ve ever wondered why your air conditioner is blowing warm air, you’re not alone. Explore the most common AC problems and fixes to troubleshoot the issue before calling a professional.

7 Common Reasons Your AC Isn’t Cooling Properly

Dirty Air Filter

A dusty filter restricts airflow and makes it harder for your AC to work. As a result, warm air blows through the vents, and your system works overtime.

The fix: Check your air filter every month and replace it as needed — usually every one to three months.

Thermostat Issues

Sometimes, the issue isn’t with your AC — it’s the thermostat. Incorrect settings or dead batteries can make it seem like your air conditioner is broken.

The fix: Set your thermostat to “cool” mode and lower the temperature. If it’s battery-operated, swap in fresh batteries. If it’s still not responding, you may need a replacement.

Low Refrigerant Level

Refrigerant is the key to air conditioning. If your system is low on refrigerant, it won’t be able to cool effectively. A leak is the most likely culprit; unfortunately, you can’t fix this problem alone.

Signs of low refrigerant include:

• Warm air blowing from the vents
• Ice buildup on refrigerant lines or coils
• Hissing or bubbling sounds from the unit

The fix: Diagnosing and repairing refrigerant issues requires specialized tools and expertise. If you suspect a leak, call an HVAC technician.

Dirty or Blocked Condenser Coils

The outdoor unit, known as the condenser, is exposed to the elements. When dirt, leaves, and debris build up on the coils, the system struggles to release heat, making your AC blow warm air.

The fix: Gently rinse the coils with a garden hose. A professional cleaning may be necessary for heavy buildup.

Frozen Evaporator Coils

The indoor unit, the evaporator, contains coils that can freeze due to restricted airflow or low refrigerant levels.

The fix: Turn off the AC and let the coils thaw. You can speed up the process with a hairdryer. In the meantime, replace the filter to improve airflow. If the coils freeze up again, call an HVAC technician for help.

Blocked or Leaky Ductwork

If your ductwork leaks or has blockages, cool air may escape before it reaches your living space, making it seem like your AC isn’t working.

The fix: Make sure your vents are open and unblocked. If you suspect leaks, schedule a professional duct inspection and sealing service.

AC Unit Is Too Small or Too Old

If your air conditioner has always struggled to keep your home cool, it might be undersized. Alternatively, if your unit is over 15 years old and constantly needs repairs, it might be getting old.

Signs it’s time to replace your air conditioner:

• Rising energy bills
• Frequent breakdowns
• Costly repairs
• Persistent comfort problems

The fix: If your system is undersized or aging, consider upgrading to a properly sized, energy-efficient model.

How Can You Fix an AC That’s Not Cooling?

Before calling an HVAC technician, try these quick troubleshooting steps:

• Check and replace your air filter if it’s dirty.
• Verify that the thermostat is set correctly and has working batteries.
• Clean the outdoor condenser coils.
• Look for ice buildup on the evaporator coils and thaw them if needed.
• Make sure all vents are open and unblocked.

If you try these steps and your AC is still blowing warm air, it’s time to call in the experts.

Get Your AC Running Efficiently Again

When you’re tired of your air conditioner running but not cooling your home, call Arronco Comfort Air for help. We’ve kept Northern Kentucky and Cincinnati, Ohio, homes cool and comfortable since 1984. Our journeyman-licensed technicians are thoroughly vetted and experienced in servicing all brands, so you can trust us for a job well done.

Are you looking for top-quality AC repairs? Contact Arronco today to schedule expert service.