Cooling · Q&A

Why is my AC blowing warm air?

Short answer: Usually one of four things: the outdoor unit lost power or a capacitor, the refrigerant charge is low from a leak, the coil froze from airflow problems, or the thermostat is calling for the wrong thing. Each has a different fix — and a different price.

Warm air with the blower running means the indoor fan is fine but nothing is removing heat. Step outside and look at the condenser: if the fan on top is not spinning while the house calls for cooling, you likely have an electrical failure — often a capacitor, one of the cheapest repairs in the trade.

If the outdoor unit runs but the air never cools, low refrigerant from a slow leak is the common culprit. A system never 'uses up' refrigerant — if it is low, it leaked, and topping off without finding the leak just schedules the same call for next summer.

Ice is the third pattern. A frozen indoor coil — from a filthy filter, blocked returns, or low charge — blocks airflow entirely, and the system blows warm while the ice slowly melts. If you see frost on the copper lines, shut the system off. Running it frozen risks the compressor, which is the most expensive component you own.

Before you call: check the filter, check the breaker, and confirm the thermostat is set to cool. Those three checks solve a surprising share of 'warm air' calls for free.

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