An air conditioner is meant to cool the room, so it’s frustrating when instead of cold air, it blows warm. I experienced this once during a hot day — the AC was running, the fan was spinning, but the air coming out felt like a heater. At first, I thought the unit had failed completely. But after checking the user manuals, I found that this issue is usually linked to a few common causes that can be fixed without major repairs.
Common Reasons Why an AC Blows Warm Air

Incorrect thermostat settings – Sometimes the unit is set to “fan” instead of “cool.”

Dirty air filter – A clogged filter restricts airflow and weakens cooling.

Low refrigerant levels – Leaks cause the system to lose cooling ability.

Blocked condenser unit – Dirt or debris around the outdoor unit prevents heat release.

Frozen evaporator coils – Ice buildup stops proper air circulation.