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Why Is My AC Freezing Up? Causes & Fixes for Metro Atlanta Homeowners

It sounds strange, but in the middle of a Georgia summer your air conditioner can literally freeze over — ice on the copper lines, weak or warm airflow, and puddles of water when it thaws. Here is why it happens and what you can do about it.

What a “frozen” AC looks like

You may notice ice or frost on the refrigerant line or indoor coil, air that is barely blowing or blowing warm, higher indoor humidity, or water pooling around the indoor unit once the ice melts. Address it before it damages the compressor — the most expensive part to replace.

The most common causes

• A dirty air filter. The #1 cause. A clogged filter starves the system of airflow, the coil gets too cold, and moisture freezes on it. In our dusty Georgia summers, filters clog fast.
• Low refrigerant or a leak. Low charge drops the coil below freezing. This needs a licensed technician — refrigerant is not a DIY fix.
• Blocked airflow. Closed or blocked vents, a dirty blower, or a collapsed return duct all reduce airflow across the coil.
• A dirty evaporator coil. Years of dust insulate the coil so it cannot absorb heat, and it ices up.
• Running the AC on a cool night. Running it below about 62°F outside can cause freezing — common on mild Atlanta spring and fall evenings.

What to do right now

1. Turn the AC off at the thermostat and set the fan to “ON” to help melt the ice.
2. Let it thaw — usually 1 to 3 hours. Never chip at the ice.
3. Replace the air filter if it is dirty.
4. Open all vents and clear anything blocking returns.
5. Once thawed, turn cooling back on. If it freezes again, the cause is deeper — call a pro.

When to call an HVAC technician

If a fresh filter and full thaw do not solve it, or it keeps freezing, you likely have a refrigerant leak, dirty coil, or failing blower — all needing professional tools and EPA certification. We offer same-day AC repair and thorough HVAC tune-ups across Metro Atlanta.

How to prevent it

Change your filter every 1–3 months, keep the outdoor unit clear of leaves and grass clippings, and schedule a professional tune-up each spring to catch low refrigerant and dirty coils before a Georgia heat wave.

Frequently asked questions

How long does a frozen AC take to thaw? Typically 1–3 hours with the fan running.

Can I keep running my AC while it is frozen? No — it can burn out the compressor. Shut it down and let it thaw.

Is a frozen AC an emergency? Not usually, but repeated freezing signals a real problem. Without cooling in extreme heat, we offer 24/7 emergency service.