AC running but not cooling?

What usually causes this

These are the common possibilities, not a diagnosis. A page cannot tell which one it is — that takes a technician testing the system.

Restricted airflow

A clogged filter, closed or blocked vents, or a crushed duct starves the indoor coil of the warm air it needs to work against. From the thermostat it looks exactly like an equipment failure.

Frozen evaporator coil

When airflow drops or the charge is low, the indoor coil can ice over. Air keeps moving but barely cools. Ice on the copper line at the outdoor unit is the visible sign.

Outdoor unit not running

If the indoor fan runs but the outdoor fan and compressor don't, the house gets moving air with no cooling. A failed capacitor or contactor is a common cause.

Low refrigerant from a leak

Refrigerant isn't used up — it circulates in a sealed loop. If it's low, it leaked. Adding more without finding the leak usually buys weeks, not years.

Dirty outdoor coil

The outdoor coil has to reject the heat pulled out of the house. Pollen, grass clippings, salt and dirt reduce that, and cooling drops even though nothing is technically broken.

Thermostat or control problem

A thermostat set to the wrong mode, calling incorrectly, or wired to the wrong stage can make a healthy system look faulty.

System too small or ducts leaking

On the hottest afternoons an undersized system, or ducts leaking cool air into a hot attic, can run nonstop and never catch up.

What you can safely check yourself

• Confirm the thermostat is set to Cool, the set point is below room temperature, and the fan is on Auto. Replace its batteries if it has them.
• Pull the air filter and look at it. If you can't see light through it, replace it.
• Make sure supply vents and return grilles are open and not blocked by furniture or rugs.
• Look at the outdoor unit: is the fan turning? Is the coil matted with debris or blocked by plants?
• Look for ice on the copper line at the outdoor unit or on the indoor coil. If you see ice, switch the system off at the thermostat and let it thaw before running it again.

What we check when we get there

1. 1A technician checks airflow first — filter, blower, coil condition and static pressure — because an airflow problem produces the same symptoms as a refrigerant problem.
2. 2Then the electrical side: capacitor, contactor and whether the compressor and outdoor fan are actually running.
3. 3Then refrigerant pressures and temperatures. If the charge is low, the next step is finding where it leaked, not just refilling it.
4. 4You get the findings in plain terms and the price to fix it before any repair work starts.

What it is likely to cost

The cost depends on what failed. A capacitor is a small repair; a leaking coil or a failed compressor is a large one and can make replacement worth discussing. You get the diagnostic price before the visit and the repair price before any work.

Diagnostic / service call

$89

Capacitor replacement

From $179

Leak detection

From $249

Leak repair + recharge

$499–$1,299

Condenser fan motor

$449–$799

Compressor

$1,799–$3,499

Prices are starting points for standard work in the Savannah area. Final price depends on the system and site, and is confirmed before work begins. Permits and code-required upgrades may be additional.

Repair or replace?

Most no-cooling calls are ordinary component repairs. Replacement becomes worth discussing when the compressor has failed, a coil is leaking, the system uses R-22 refrigerant, or repairs have started to pile up on a system past about 12–15 years old.

Questions people ask about this

Why is my AC blowing warm air?

Usually because the outdoor unit isn't running, the indoor coil has frozen, or the refrigerant charge is low from a leak. Check the thermostat mode and the filter first. If the air stays warm, it needs a diagnostic visit.

My AC runs all day and never reaches the set temperature. Is that broken?

On the hottest afternoons a correctly sized system may run for long stretches — that's normal. If it never catches up even into the evening, something is limiting capacity: airflow, charge, a dirty coil, or duct leakage.

Can I just add refrigerant?

Not safely or legally without certification, and it doesn't fix anything on its own. Refrigerant doesn't get used up, so a low charge means there's a leak that needs finding.

Should I keep running it?

If you see ice, or the outdoor unit is humming without the fan turning, switch it off at the thermostat. Running it that way can damage the compressor.

Where to go next