Why is my AC running but not cooling?
An AC that runs but won't cool usually comes down to airflow or refrigerant: a clogged filter or frozen coil chokes airflow, while a refrigerant leak or a failed capacitor or compressor stops the cooling itself. Some you can check; others need a technician.
Things you can check first
- Thermostat: set to COOL and below room temperature, with fresh batteries.
- Air filter: a clogged filter starves airflow and can freeze the coil — replace it if it's dirty.
- Outdoor unit: clear leaves, grass and debris from around the condenser so it can shed heat.
- Vents and returns: make sure supply and return vents aren't blocked by furniture or closed off.
Signs it needs a technician
- Ice on the refrigerant lines or indoor coil — turn the system off and let it thaw; recurring ice usually means low refrigerant or airflow problems.
- Warm air with the outdoor fan not spinning — often a failed capacitor or contactor.
- A hissing or bubbling sound, or cooling that fades over weeks — a possible refrigerant leak.
- The breaker keeps tripping — stop and call; that's an electrical fault, not a reset-and-retry.
Why it happens more here
In Fort Bend's heat and humidity, a system that's low on refrigerant or short on airflow shows it fast — the unit runs constantly and still can't keep up. Catching it early usually means a smaller repair than waiting until a July breakdown.
Common questions
Why is my AC blowing warm air?
Common causes are a dirty filter or frozen coil choking airflow, a low refrigerant charge from a leak, or a failed capacitor stopping the compressor. Check the filter and thermostat first; if it's still warm, it needs a diagnostic.
Should I add refrigerant myself?
No. An AC that's low on refrigerant has a leak, and simply adding more only masks it for a while. Refrigerant handling is regulated and requires an EPA-certified technician who fixes the leak first.
How we build this guidance
This guide is written and reviewed by the Lazarine AC team — a local heating, cooling and electrical company serving Fort Bend County since 2000. It reflects how we actually diagnose and quote work here, not generic national copy. It's general information, not a substitute for an on-site diagnosis of your specific system.
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