It's 94 degrees, the thermostat says 78, and the air from the vents feels like a warm sigh. "AC not cooling" is the most common call we get in Florida from May through October. Here are the causes we find most, roughly in order of how often we see them.
1. Dirty air filter
A clogged filter chokes airflow across the evaporator coil. The coil gets too cold, ices over, and cooling drops to almost nothing. Check the filter first — in Florida, most homes need a new one every 30–60 days.
2. Frozen evaporator coil
If you see ice on the copper lines or the indoor coil, the system has an airflow or refrigerant problem. Turn cooling off, switch the fan to On, and let it thaw for a few hours before a technician arrives. Read more on our
AC not cooling page.
3. Low refrigerant (a leak)
Refrigerant doesn't get "used up." If it's low, there's a leak. Topping it off without finding the leak is a short-term patch. A proper
AC repair locates and seals the leak.
4. Failed capacitor or contactor
The outdoor unit hums but the fan won't spin, or nothing outside runs at all. Capacitors are the most common part to fail in Florida heat and one of the cheaper fixes.
5. Dirty condenser coil
Grass clippings, dust and salt air coat the outdoor coil so it can't dump heat. A coil cleaning during an
AC tune-up often restores lost capacity.
6. Thermostat problems
Dead batteries, a wiring fault, or a thermostat set to Fan On instead of Auto will all produce warm air.
7. Compressor failure
The most serious cause. Breakers tripping when the AC starts, loud hard-starting, or an outdoor unit that runs but never cools points to the compressor. See
AC compressor repair.
8. Duct leaks
In Florida attics, leaking supply ducts can dump 20–30% of your cold air into 130-degree attic space.
9. Undersized or aging system
A 15-year-old unit on a hot afternoon may simply not keep up anymore. If repairs are stacking up, compare against
AC replacement.
When to call
If the filter is clean and the coil isn't frozen, stop troubleshooting — running a low-charge or failing system risks the compressor. Citywide HVAC Services offers same-day AC repair in every Florida city. Find your town on our
locations page or call (855) 459-5498.
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