Why is my AC not cooling? A South Florida diagnosis guide

It's the most posted problem on this platform, usually with the phrase "house is 84 degrees." Here's how pros actually narrow it down, and what the common outcomes cost.

Runs but doesn't cool

• Dirty filter or frozen coil. Embarrassingly common, occasionally free to fix. Change the filter, let the coil thaw, see what happens. A seasonal tune-up (~$90–$200) prevents most of it.
• Low refrigerant. The system doesn't "use up" refrigerant — if it's low, it leaked. A recharge (~$200–$550) restores cooling, but an honest tech will talk to you about finding the leak, because recharging a leaky system is a subscription.
• Dirty condenser coil. The outdoor unit breathing South Florida's salt-and-lawn-clippings air needs cleaning to reject heat. Often part of a tune-up.

Doesn't turn on, hums, or clicks

• Capacitor. The single most common "AC died overnight" diagnosis — the start/run capacitor cooks in our heat. The replacement typically runs $150–$400 and takes under an hour.
• Thermostat or breaker. Worth checking yourself before the call.

The replacement conversation

If the system is 12+ years old, uses phased-out refrigerant, and the repair quote crosses ~$1,500, replacement math usually wins — newer systems also sip electricity by comparison, which matters at FPL's rates. Full systems are quoted on-site; insist on a load calculation, not a "same size as the old one."

Skip the fifteen unanswered calls — post the task free and mark it Emergency; nearby HVAC pros are notified immediately.