Warm air from the vents means the cold isn't being made
Your AC has two jobs: move air, and chill it. Blowing-but-not-cold means job one works and job two failed. That points at the outdoor unit (compressor, capacitor, refrigerant) or at a coil that can't do its work.
Step 1: Check the thermostat mode
It sounds silly, but "ON" instead of "AUTO" makes the fan blow room-temperature air between cooling cycles — people feel warm air and assume the AC broke. Set it to COOL, fan on AUTO, temperature 5 degrees below the room. Wait five minutes.
Step 2: Go look at the outdoor unit
- Fan spinning, low hum, air from the top feels warm: normal — that's your house's heat leaving. If the vents inside still blow warm, suspect refrigerant.
- Fan spinning but the unit clicks or hums loudly every few minutes: the compressor may be trying and failing to start — often a capacitor, one of the cheapest fixes in HVAC.
- Nothing running at all outside: check the breaker and the disconnect box by the unit. If it has power and stays silent, the outdoor unit needs a tech.
Step 3: Look for ice
Ice on the copper lines or on the indoor coil means the system froze itself — airflow or refrigerant trouble. Turn cooling off, run the fan to thaw, and read our frozen lines guide before you do anything else.
When it's serious
If the compressor itself has failed on an older system, that's the one repair where replacement often makes more sense than fixing. We'll give you both numbers honestly — repair vs. replace — and the reasoning, so you decide with real information.