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AC Freezing Up
in Fort Lauderdale, FL
It sounds backwards, but your AC can freeze solid right in the middle of a Fort Lauderdale summer. When airflow across the evaporator coil drops too low, the coil gets too cold and ice builds up. The same thing happens when refrigerant is low. Either way, the ice blocks airflow completely and your home stops cooling. Running a frozen unit can damage the compressor.
Quick Answer
Ice on your AC unit means airflow is blocked, refrigerant is low, or the system is running in conditions it can't handle. In Fort Lauderdale, the most common cause is a clogged air filter combined with August heat that pushes the system to run nonstop. Turn the system to fan-only to melt the ice first. Then call (754) 354-3070 to find out what caused it before you run it again.
Telltale Signs
Warning Signs to Watch For
- Ice visible on the copper lines coming out of the indoor unit
- Ice buildup on the indoor air handler cabinet itself
- Warm air blowing from vents even though the system is running
- Water dripping or flooding from the air handler when the ice melts
- System shuts off on its own and restarts after a while
Root Causes
What Causes AC Freezing Up?
Restricted Airflow From Clogged Filter
The evaporator coil needs a steady flow of warm indoor air passing over it to stay above freezing. When the air filter clogs up, that airflow drops and the coil gets too cold. Fort Lauderdale homes with pets or near construction zones in areas like Flagler Village can clog a filter in 3 to 4 weeks during peak season.
The Fix
Filter Replacement and Airflow Check
Swap out the filter and let the ice melt completely before restarting the system. A tech should also check that all supply and return vents are open and that duct sizing is adequate for the air handler.
Low Refrigerant Charge
Refrigerant absorbs heat as it passes through the evaporator coil. When the charge is low, the refrigerant pressure drops too far and the coil surface gets cold enough to freeze the humidity in the air around it. Slow leaks from corroded fittings are common in Fort Lauderdale's coastal air.
The Fix
Leak Repair and Refrigerant Recharge
A tech finds the leak, repairs it, and adds refrigerant back to the correct level. Just adding refrigerant to a leaking system is a short-term fix. The leak has to be sealed.
Blocked or Closed Supply Vents
Closing vents in unused rooms seems like it would save energy, but it actually reduces airflow across the coil and can cause freezing. This is a misunderstanding that shows up in a lot of older Fort Lauderdale homes where owners are trying to reduce their FPL bills.
The Fix
Vent and Duct System Correction
A tech checks all vents in the home and makes sure they're open and unobstructed. In some cases, the duct system needs to be rebalanced to match the air handler's actual airflow requirements.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Restricted Airflow From Clogged Filter | Low Refrigerant Charge | Blocked or Closed Supply Vents |
|---|---|---|---|
| Air filter was black or hadn't been changed in months | |||
| Ice returned after thawing with no filter change | |||
| Several room vents were closed before the freeze happened | |||
| Hissing sound near the outdoor unit before freezing started | |||
| Problem started during a stretch of days above 95 degrees |
Free Inspection
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