Why does my AC keep freezing up?

An AC freezing up usually means something is interfering with airflow or refrigerant circulation. In Florida’s humid climate, this is pretty common. Here are the most common causes:

❄️ Reasons Your AC Freezes Up

1. Dirty Air Filter – A clogged filter restricts airflow, making coils too cold.
2. Blocked or Closed Vents – If return or supply vents are shut, air can’t circulate properly.
3. Low Refrigerant Levels – Leaks cause pressure drops, which lowers coil temperature and creates ice.
4. Dirty Evaporator Coils – Dust and dirt act as insulation, preventing heat absorption and causing freezing.
5. Blower Fan Problems – If the fan isn’t moving enough air across the coils, they’ll ice up.
6. Running AC in Cool Weather – If nighttime temps drop too low (below ~65°F), coils may freeze.
7. Thermostat or Airflow Issues – If the system short cycles or runs constantly, freezing is more likely.

✅ What You Can Do First

• Turn off the AC and switch the thermostat fan setting to ON (this melts the ice faster).
• Check and replace the air filter if it’s dirty.
• Make sure vents are open and furniture isn’t blocking airflow.
• Inspect the outdoor unit for dirt, debris, or airflow blockages.

⚠️ If the unit keeps freezing up after these steps, it’s likely a refrigerant leak or blower issue, which needs a Klein Cooling HVAC technician.