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“Why is my AC blowing hot air?” The answer to this question below from our Los Angeles, CA HVAC experts.

The last thing you want on a hot and humid day is to feel hot air blowing from your AC.

Don’t worry—we’ll help you troubleshoot this frustrating problem.

First, go to your thermostat and verify the following:

  • Make sure the thermostat is set to COOL

  • Check that the fan setting is set to AUTO so that the AC will only push air into your home if it’s cooled

If your thermostat is set correctly but you still feel warm air, your air conditioner may have one of the following problems:

  1. A frozen or dirty evaporator coil

  2. A dirty outdoor unit

  3. An issue with the compressor

We’ll explain all of these issues in more detail below. And we’ll tell you right off the bat that some of these problems require professional expertise to fix. So if you’d rather skip the explanations and get help ASAP, go ahead and call an AC pro for assistance.

Want a Los Angeles professional to repair your AC? Our techs are standing by, ready to help.

Problem #1: A frozen evaporator coil

The evaporator coil (located in the inside unit) is the AC part that actually cools your home’s warm air.

Inside the evaporator coil, a liquid substance called refrigerant absorbs heat from warm air as it passes over the coils, turning the air cold. This cold air is then pushed back into your home to lower the indoor temperature.

However, if the evaporator coil freezes over, you’ll start to have problems. Though it may seem like really cold coils will make your home’s air super cold, the opposite is true. If the coils get too cold and end up freezing over, the ice buildup will create a barrier that prevents the refrigerant from absorbing heat.

The result? The air being pushed out of your vents will be warmer, and your AC will struggle to cool your home.

How to know if you have a frozen evaporator coil

Besides the hot air issue, the following signs also indicate you may have a frozen evaporator coil:

  • A musty smell around the air handler

  • Pools of water around the air handler

  • Ice buildup on the outdoor refrigerant lines

What causes a frozen evaporator coil (and how to fix it)

The most common problems that cause an evaporator coil to ice over include:

  • Airflow restrictions, such as a dirty air filter or closed vents

  • Refrigerant leaks

  • Fan issues

  • Dirt buildup on coils

The first thing you’ll want to do is make sure your air filter is clean and that all vents in your home are open and unobstructed.

If the hot air problem persists after you’ve inspected the air filter and vents, your AC may have one of the other problems we mentioned, such as a refrigerant leak or a broken fan. These issues are complex and require extensive HVAC knowledge to fix, so it’s best to hire a professional.

We also do not recommend cleaning the evaporator coil yourself because the coils are fragile and can be easily damaged. An HVAC professional will have the proper tools and equipment to clean the coils safely and effectively.

Problem #2: A dirty outdoor unit

Above, we discussed how refrigerant absorbs heat from your home’s warm air at the air handler. This is the first phase of the cooling process. The next phase of the cooling process takes place in the outdoor unit.

The purpose of the outdoor unit is to release the heat absorbed by the refrigerant. When the hot refrigerant reaches the outside unit, the condenser coil helps dissipate the heat into the outdoor air. This allows the refrigerant to cool down before it’s sent back to the indoor unit, where the refrigerant can absorb more heat and continue cooling your home.

That said, if the condenser coil or the fins around the outdoor unit are dirty, your AC will struggle to release the heat. In turn, this leads to overheating problems and can cause your AC to blow warm air into your home.

How to clean a dirty outdoor unit

First, make sure there are no leaves or debris stuck inside the fins around the outdoor unit. If you see significant dirt buildup on the fins, you can use a hose (on a medium or low setting) to spray them down.

To clean the condenser coil itself, start by shutting off power to the outdoor unit. (You’ll see a small electrical box on the wall next to the outdoor unit.)

Next, remove the top of the condenser and locate the copper lines inside the outdoor unit. If these copper lines appear dirty, you can apply some *coil cleaner to them. Set your hose to a low setting and spray the coils from top to bottom, but be careful not to soak the fan motor.

*Pro tip: Before purchasing coil cleaner, we recommend consulting with the AC manufacturer or an HVAC tech. They can recommend a cleaner that will work effectively without damaging the coils.

After you gently rinse the cleaner off of the coils, you can reattach the condenser lid and turn on the power again. If the hot air problem persists, or you don’t want to clean the coils yourself, contact an HVAC professional for assistance.

Problem #3: An issue with the compressor

The compressor is a major AC component located in the outdoor unit of your air conditioner. The purpose of the compressor is to circulate refrigerant throughout the AC system.

If the compressor is malfunctioning, the entire cooling process will suffer, leading to higher indoor temperatures and wear and tear on several AC components.

How to know if your compressor is malfunctioning

Besides the hot air issue, the following signs also indicate your compressor is struggling:

  • Loud noises or vibrations coming from the outdoor unit

  • The outdoor unit isn’t turning on at all

  • The AC circuit breaker keeps tripping

How to fix a malfunctioning compressor

Unfortunately, if your compressor is acting up, there’s not much you can do to fix it yourself. You’ll need to contact an HVAC professional to inspect the compressor.

Need an AC repair from a Los Angeles tech?

Call the Experts at SoCal Climate Control TODAY at 833-202-0763

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What others say


In the 5 years that I have lived in my SF valley home, I have had my AC and furnace die on me. Mike and his team gave me a great deal on new HVAC system, and 2 years later the furnace. I work in the construction industry, and confirmed quality installation and equipment. They paid attention to the little things too, which carries over in my experience. SoCal did maintenance, and the technician Dave recommended improving the duct intakes and filter system. Cannot wait for my home to be colder than a polar bear’s toenails this summer.

David Sire

Wonderful company! From the moment they came to give us a bid for their services to the last minute they were here. Very professional, knowledgeable, and genuine. You will not spend any money you don’t need to spend, they are honest about the work your home needs done, but also honor whatever services you’d like to have done. They respond quickly, and promptly. We had our vents/registers cleaned, old ducts removed, & new ones installed, they took care of the whole process leaving nothing behind. Charles and his crew were great! Respectful, professional, and always on time. Would highly recommend.

Maria Hoz

Mike sent his team out when our AC failed on the hottest day. It was a late Saturday afternoon and we were staring down having to wait until Monday at the earliest to get someone out. Mike immediately told me his team would be there within 90 minutes, and they showed up on a Saturday evening within the hour! Great service!

Mary Goldstein

Overall, this was a very good experience. Customer service was great! The price was reasonable. Installation was scheduled 2 days after we purchased the HVAC system,. They installed the system in approximately 5 hours, and there was no mess. This a very professional operation

Joseph Pecot

I have been unbelievably impressed and overwhelmingly happy with the quality of the service provided by the team at So Cal Climate Control. From the initial estimate to the install and everything else, everyone we’ve had on this project has been so friendly, professional, and detail oriented. Highly recommend this company if you are looking for HVAC work.

Julie Matos

So Cal Climate Control was Home Adviser’s first choice, so I called and talked to dispatch. I had a technician ( Chris) at my door within 2 hours.
He was professional, courteous and their price was reasonable.

James Fisher

Just the best service, honest, reliable company!! Have a new unit, love it.. and have told many people to use this company. I had 3 bids when I was looking for unit and sooo happy I went with my gut feeling! The best, they come out and service too, extremely happy.

Jodi Lasky

Angel and Robert were professional and installed a great system of the highest quality. It runs cold and quiet; what more could one ask for?? Great company; great staff; highest of quality and the highest of recommendation.

Joe Baratta

Your Expert you send out was so honest with me he was so nice and professional he told me what to do that I didn’t need what I thought I did I’m so use to people coming out and try to take me to the cleaners specially I’m a Senior a Woman and living alone if I ever need any service done I will call you in a Heartbeat you r Technician Danny was super nice and very Professional I’m so glad I found this Company

Ondina Santa Maria

Great people. A year ago they replaced my duct work so called them when I needed a new furnace. Prompt, quick turn around and very professional. I totally recommend this company!! On the same day, they installed a tankless water heater. These peeps are amazing!

LuAnn Hughes

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