Every June, a Dallas homeowner sends us the same photo: a copper pipe wearing a sleeve of ice while the backyard bakes at 100°. It looks impossible. It's actually one of the most predictable failures in air conditioning — and what you do in the first ten minutes matters a lot.
First: turn it off
A frozen AC that keeps running can slug liquid refrigerant into the compressor — the one component whose replacement cost rivals a whole new system. Switch the thermostat to OFF and the fan to ON. The fan will melt the ice in a few hours while you figure out the cause. Put towels around the indoor unit; that ice becomes water.
Why cold + broken = ice
Your AC works by making an indoor coil very cold and blowing your warm house air across it. Two things keep that coil just above freezing: plenty of warm air moving across it, and the right amount of refrigerant inside it. Take away either one and the coil's temperature crashes below 32°. Humid Texas air then does the rest, condensing and freezing into an ice block that chokes what little airflow remained.
The usual suspects, in order
In Dallas homes, we find these causes most often:
- A severely clogged filter — the #1 cause, and the one you can fix yourself today.
- Refrigerant leak — low charge drops coil pressure and temperature. Needs professional leak detection and repair.
- Failed blower motor or weak capacitor — the coil is cold but nothing is moving air across it.
- Blocked or closed vents — closing vents in unused rooms (a popular 'savings' myth) can starve airflow enough to freeze the coil.
- A dirty evaporator coil — years of dust acts like a blanket between the air and the coil.
After the thaw
If a filthy filter was your culprit, replace it, run the system, and watch it for a day. If it freezes again — or the filter looked fine — the cause is refrigerant or mechanical, and it will keep freezing until it's actually repaired. Ice is a symptom, not the disease.
One more Texas-specific note: freezing accelerates on the hottest weeks precisely because the system runs continuously with no recovery time. That's why these calls stack up during heat waves — and why a spring tune-up that catches weak capacitors, low charge, and dirty coils prevents most of them.
From the team at Strike Force HVAC
AC icing up? We'll find the real cause — same-day service across DFW.