Why is my AC running but not cooling?
When the system runs but the house won't cool, the cause is almost always one of a short list: a clogged filter, a frozen coil, low refrigerant from a leak, a failing electrical part, a tripped condensate safety switch, or leaky ducts. A few are safe to check yourself; the rest need a technician.
Work through the checklist below in order before you call. It often turns a stressful no-cool afternoon into a five-minute fix — and if it doesn't, you'll know it's time for a pro.
The Florida no-cool troubleshooting checklist
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Check the thermostat settings
Make sure it's set to COOL (not just FAN or AUTO-fan) and the target temperature is below the room temperature. Try fresh batteries if the screen is dim or blank — a dead thermostat can stop a healthy system from cooling.
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Inspect and change the air filter
A clogged filter is the single most common cause of weak cooling. If it's dirty, replace it. In Florida's long cooling season, check the filter every 1–3 months. A choked filter can also freeze the coil.
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Check your breakers and the outdoor disconnect
Look for a tripped breaker for the air handler or condenser and reset it once. If it trips again immediately, stop — that points to an electrical fault that needs a professional.
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Look at the outdoor unit
Confirm the outdoor condenser fan is spinning and the unit is clear of leaves, grass clippings, and debris. Gently rinse heavy dirt off the coil fins with a hose. Near the beaches, salt buildup on the coil is a common culprit.
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Check for ice on the refrigerant lines or coil
If you see ice on the copper lines or the indoor coil, turn the system OFF and let it fully thaw. Running a frozen system can damage the compressor. A frozen coil usually means a dirty filter, low refrigerant, or airflow problem that needs attention.
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Make sure vents and registers are open
Walk the house and confirm supply registers aren't closed or blocked by furniture or rugs. Too many closed vents can throw off airflow and pressure across the system.
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Check the condensate drain and safety switch
In our humidity, a clogged condensate drain line trips a safety float switch that shuts the system off to prevent water damage. If the air handler won't run and there's standing water near it, the drain may be clogged — a frequent Florida service call.
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Still not cooling? Call a licensed technician
If the basics check out and the home still isn't cooling, the cause is likely low refrigerant from a leak, a failing capacitor or compressor, or leaky ductwork — all of which need a professional. Anna's offers same-day service across the Space Coast.
Safety first
Stick to the homeowner-safe checks above — filters, thermostat, breakers (reset once), and clearing debris. Don't open the sealed refrigerant system or electrical panels. If a breaker trips again, you smell burning, or you see ice, stop and call a licensed technician.
When to stop and call a pro
Some symptoms mean the DIY portion is over. Call a licensed technician right away if you notice:
- Ice on the refrigerant lines or indoor coil that returns after thawing.
- A breaker that trips again the moment you reset it.
- Burning smells, grinding or buzzing noises, or the outdoor fan not spinning.
- Warm air at the vents with a clean filter and correct thermostat settings.
The common Florida causes, explained
Here's what's usually behind a no-cool call once the basics are ruled out:
- Low refrigerant from a leak. The system can't absorb heat properly and may freeze. Adding refrigerant without fixing the leak is a temporary band-aid.
- Failing capacitor or compressor. The capacitor starts the motors; a weak one is a common, affordable fix. A failed compressor is a major repair that often tips toward replacement.
- Dirty coil. A grimy evaporator or salt-caked condenser coil can't transfer heat — common on the barrier islands.
- Leaky ductwork in a hot attic, dumping cooled air before it reaches your rooms.
If the fix turns out to be major, our repair-vs-replacement guide helps you decide whether to fix or replace, and how air conditioning works explains the parts involved.
How Anna's helps
When the checklist doesn't fix it, our woman-owned team gets to you fast — same-day service across Brevard County and 24-hour emergency response. We diagnose the real cause, explain your options honestly, and never upsell a repair you don't need, all backed by our 365-Day Money-Back Guarantee.
The best way to avoid a no-cool day in the first place is regular maintenance — see how often you should service your AC in Florida.