AC not cooling or blowing warm air
The system is running, but the air isn't cold and the house keeps getting warmer. Here's what usually causes it, what you can safely check, and when to call.
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"Not cooling" has many causes, from a thermostat setting to a failed capacitor to a refrigerant leak. Air that is cool but not cold, or a house that can't get below 78°F on a hot afternoon, are different symptoms from air that is plainly warm. Telling us which one you have helps us send the right parts.
What you might notice
- Air from the vents feels room temperature or warm
- The indoor fan runs but the outdoor unit is silent, or its fan isn't turning
- The house slowly gains temperature through the afternoon
- Ice on the copper lines near the outdoor or indoor unit
- The system runs nonstop without reaching the set temperature
Common causes
Outdoor unit not running
A failed capacitor, contactor or fan motor, or a tripped breaker or disconnect. Very common in constant-use Florida systems.
Restricted airflow
A clogged filter, blocked returns or a dirty evaporator coil reduce cooling and can freeze the coil.
Dirty outdoor coil
Grass clippings, dirt and salt on the condenser coil stop it from rejecting heat.
Low refrigerant
Refrigerant doesn't get used up. If it's low, there's a leak that needs to be found and repaired.
Thermostat or controls
Wrong mode, wrong setpoint, a fan set to On, or a failing thermostat or control board.
Safe checks you can make first
- Confirm the thermostat is on Cool, set below room temperature, fan on Auto
- Replace a dirty filter
- Check the AC breakers and the outdoor disconnect; reset a tripped breaker once only
- Look at the outdoor unit: is the fan spinning? Clear debris and plants back at least two feet
- If you see ice, switch to Off or Fan only and let it thaw
How a Uniform technician diagnoses it
We work in order: thermostat and power, then filter and airflow, then the indoor coil and drain, then the outdoor unit's electrical components and fan, and finally the refrigerant circuit. We measure the temperature difference between return and supply air, check voltages and amperage, and only connect gauges when the other checks point that way. If refrigerant is low, we search for the leak before discussing a charge.
Repair options
| Option | When it fits |
|---|---|
| Replace a capacitor, contactor or fan motor | The outdoor unit isn't running or the fan isn't turning. |
| Clean coils and restore airflow | Dirty coils or a clogged filter are reducing cooling. |
| Find and repair a leak, then recharge | Refrigerant is low and the leak is repairable. |
| Replacement assessment | A compressor or coil has failed on an older system. See repair or replace. |
You get a written estimate after diagnosis and before any work starts. See what changes a quote in our Naples AC repair cost guide.
Why homeowners choose Uniform
The technician who comes to your home has passed a guaranteed background check and works for a licensed, insured air conditioning contractor. Florida license number posted at launch. Verify any Florida A/C contractor at DBPR.
Request a call back
Tell us what's happening and we'll call you to schedule. Every visit starts with diagnosis and a written estimate.
Other AC problems: ac won't turn on, ac leaking water, frozen ac coil, weak airflow, ac runs constantly, thermostat problems, ac noise or smell, high ac electric bill, heat pump problems.
Frequently asked questions
Why is my AC running but not cooling?
Most often the outdoor unit has stopped (capacitor, contactor or fan motor), airflow is restricted, or refrigerant is low from a leak.
Can I just add refrigerant?
No. Refrigerant handling requires EPA certification, and adding it without fixing the leak means it will leak out again.
Is it OK to keep running it?
If the outdoor fan isn't spinning or there's ice, no. Turn cooling off to protect the compressor and call.
Need an HVAC tech you can trust in your home?
Call now. We'll ask a few questions, give you an honest arrival window and send a background-checked, licensed technician in uniform.
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