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What To Do When Your AC Is Blowing Warm Air

June 3, 2025

You turn on your air conditioner expecting crisp, cool air, but instead, you’re hit with a wave of warm air from the vents.

When your AC is blowing warm air, it’s a sign something’s not working right. Whether it’s a quick fix or a more serious repair, knowing how to respond can help you avoid bigger problems and restore comfort fast.

At ProThermal Heating and Cooling, we help Tulsa homeowners quickly identify and resolve AC issues before they turn into expensive breakdowns. Here’s what you need to know.

Common Causes of Warm Air Blowing From Your AC

There are several reasons why your air conditioner might stop cooling. Some are simple to fix, while others require professional diagnosis. Common causes include:

Incorrect Thermostat Settings

It happens more often than you think. Your thermostat may be set to “heat” or the fan set to “on” instead of “cool” and “auto.” This causes your system to circulate air without actually cooling it.

Tripped Circuit Breaker

A tripped breaker can shut off the outdoor condenser unit while the indoor fan continues to blow air, resulting in warm airflow.

Dirty Air Filter

Clogged filters restrict airflow, prevent efficient cooling, and can eventually cause parts like your evaporator coil to freeze.

Frozen Evaporator Coils

When airflow is restricted, the coils inside your unit can freeze up. This blocks the cooling process and may cause warm air or no airflow at all.

Low Refrigerant Levels

Low refrigerant (or a leak) prevents your AC from removing heat from the air. Signs include ice buildup, hissing sounds, or a chemical odor.

What You Can Try Before Calling for Service

If your AC unit is blowing warm air, start with these simple steps:

  • Check your thermostat and make sure it’s set to cool and auto
  • Set the temperature between 60–75°F for proper cycling
  • Inspect your breaker panel – if a breaker has tripped, turn it fully off before switching it back on
  • Replace your air filter if it looks dirty or clogged
  • Clear any debris from around the outdoor condenser unit, including leaves or grass buildup

If your system doesn’t start cooling after these steps, it’s time to bring in an HVAC pro.

When To Call a Professional

Some AC issues should never be handled on your own. Call ProThermal if:

  • You hear hissing, smell refrigerant, or see ice on the refrigerant line
  • The unit continues blowing warm air after checking settings and replacing the filter
  • Your system frequently cycles on and off or doesn’t respond at all
  • The evaporator coil keeps freezing, even after filter changes

These symptoms may signal refrigerant leaks, compressor issues, or electrical problems, all of which require trained, certified HVAC professionals.

Keep It From Happening Again

The best way to avoid warm air problems? Routine maintenance. Regular AC tune-ups help prevent airflow restrictions, refrigerant leaks, and overheating.

We recommend:

  • Replacing filters every 1-3 months
  • Scheduling seasonal AC maintenance before peak summer
  • Keeping the outdoor unit clean and clear
  • Installing a smart thermostat to catch temperature swings early

Restore Comfort With ProThermal Heating and Cooling

When your AC is blowing warm air, don’t sweat it – just call ProThermal Heating and Cooling at (918) 212-0258 for fast, expert AC repair in Tulsa and the surrounding areas. We’ll get your system back to blowing cool, clean air in no time.


Want more tips, HVAC advice, and local insights? Listen to our radio show, Complete Home Comfort, on KRMG. We cover all things heating, cooling, and home comfort solutions.

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Bruce Isentol profile picture
Bruce I
7 September 2026
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Grant is personable, knowable, and most importantly honest. Because of him Ill call Protherm next time I have a problem.
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Sdawn M profile picture
Sdawn M
5 September 2026
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Excellent experience with Pro Thermal. They might not be the lowest quote you receive, but their craftsmanship, attention to detail, and professionalism make it worth every penny. The team was punctual, respectful of our home, and fixed the issue properly. If you value quality work over cheap quick-fixes, hire Pro Thermal.
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Elianny P
5 September 2026
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They explained every detail about my Air Conditioning and did a great Service
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Maria Soto profile picture
Maria S
5 September 2026
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Excellent Service and technicians have a lot of knowledge
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Brook Koch profile picture
Brook K
5 September 2026
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Prothermal is phenomenal, helped my buddy at his OU football game get together. They are coming out to check my system next week after what I seen. This company doesn’t mess around. They truly want you to spend less on your utilities. Invited my heat and air company before this tech left!!!
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Jim D
5 September 2026
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Man Prothermal is something special. My AC went down as OU kicked off and they showed up promptly and quickly got my system up and running. Not only that still spent more time looking over my entire system! Extremely through and made it to where me and my crew could enjoy the game! If you call anyone else you are just not getting a complete service!!
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Mike B
4 September 2026
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Dawson was very courteous, and got my ac up and running real fast. Good stuff all around.
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Pam M
3 September 2026
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Grant was an amazing technician. He was able to determine an issue we’ve dealt with for 2+ years that a previous company chose to ignore. I recommend their services to everyone!
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Reggie C
3 September 2026
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Dawson was Awesome, he went far and beyond, thank you Dawson
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Michelle G
3 September 2026
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Excellent info. And he did a great job of explaining every detail thoroughly. Answered all my question and was patient w me. He was exceptionally wise!
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