AC Is Freezing Up-- Now What?

Written by the team at Heat and Air Gurus — your HVAC problem-solvers in DFW

The $129 Ice Cube: A True Story from the Field

Last night around 8pm, I was out servicing a familiar home—my 3rd grade teacher Ms. Knighton. Her AC had stopped cooling, and by the time I got her back to comfortable, I was already on call number two.

The next customer called just before dinner, and since it was after-hours, I let him know it’d be a $129 investment for the visit. He agreed, and off I went.

As soon as I got to his house and walked to the outdoor unit, I saw it immediately: his AC was frozen solid.

I looked him dead in the eye and said, “Well… you just paid me $129 for 12 seconds of work.”

Nothing I could do until it defrosted.

I gave him a choice:

• Pay me to sit there for an hour and watch the ice melt

• Or shut the system down and run the heater for a bit to speed up the thaw

His kids were getting ready for bed and comfort mattered, so he elected for me to come back in the morning.

That visit inspired this blog—because this didn’t have to happen. Let’s talk about why AC units freeze up, what to do if it happens, and how to prevent it in the first place.

First Things First: Check This When Your AC Stops Cooling

When your air conditioner isn’t keeping up, don’t panic. Go through this checklist before calling in the cavalry:

1. Go outside and check if the AC unit is running.

   
   

   • If it’s not, check the breaker and the float switch (usually in the attic near your indoor unit or pan).

2. If it is running, inspect the copper refrigerant lines (the ones connecting the outdoor unit to the home).

   
   

   • Is there ice buildup on the lines?

   • Is the larger line cold and sweating like a glass of ice water?

     
     

     • If it’s not sweating, that often means you’re low on refrigerant or there’s another issue affecting performance.

       
       

     • This quick triage helps you determine whether it’s a simple electrical issue, airflow restriction, or refrigerant-related.

AC Not Cooling? Go outside and check to is if your AC looks like this one...

Dirty filters can also cause AC to freeze

What Causes an AC to Freeze Up?

If your system is turning into an icebox, it’s not just bad luck. Here are the most common culprits:

• Low refrigerant – Usually from a leak. Low pressure causes the coil to get too cold.

• Airflow issues – Dirty filter, clogged evaporator coil, or a dusty blower wheel can choke off airflow.

• Undersized or poorly designed ductwork – If your return air is restricted, it can cause the coil to freeze.

• Dirty evaporator coil – Even a thin layer of dust acts like a sweater on your coil.

• Combination of the above – Often, it’s not just one thing. HVAC systems are ecosystems, not single parts.

What to Do if Your AC Is Frozen

So you went outside and found a popsicle where your AC unit should be. Here’s how to handle it:

✅ Step 1: Call a 5-Star AC Company You Trust

This isn’t the time to gamble. A frozen AC is usually a symptom of a bigger problem. At Heat and Air Gurus, we’ve fixed thousands of these issues and can walk you through it with honesty and transparency.

✅ Step 2: Shut Off the Outdoor Unit

Flip the breaker or pull the disconnect outside. You need to stop refrigerant flow to prevent further freezing.

✅ Step 3: Leave the Indoor Fan Running

Switch the thermostat to “Fan On” (not Auto). Moving air helps melt the ice.

✅ Step 4: Monitor for Leaks

Keep an eye on your indoor unit and drain pan. Sometimes, ice forms beyond the pan and as it melts, it can spill into your attic. If water starts to drip through the ceiling, that’s an emergency.

Pro Tip: Don’t Pay Someone to Watch Ice Melt

This sounds funny, but we see it all the time. The most efficient way to deal with a frozen AC is to start the defrost process ASAP, then call once it’s thawed.

Better yet? Let’s prevent this from happening.

How to Prevent Your AC from Freezing Up

Here’s how you can keep your system healthy and avoid late-night service calls:

• Change your filters monthly (or more if you have pets or allergies)

• Schedule annual maintenance with a pro to clean coils, check pressures, and inspect ductwork

• Make sure your return ducts are properly sized

• Keep your drain line clear

• Invest in a static pressure test if you suspect airflow issues

Final Word: Don’t Wait for a Freeze-Up to Call

If your system’s been acting up—or if you want a second opinion from someone who actually cares more about your comfort than the upsell—we’re your guys.

📍 Based right here in Carrollton/Plano, Heat and Air Gurus is the go-to for DFW families who want honest advice, fast service, and no pressure.

Give us a shout before your system turns into an ice sculpture.

Call Heat and Air Gurus today or book online!

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469-797-1269 (1COW)