Why does your central air unit blow out hot air from the vents?

Your air handler is working but the compressor outside isn't. The air handler is responsible for pumping the cooled air through the vents and into your house. It may be located in the attic, basement, or perhaps the garage. The compressor/heat exchanger is outside. If it is damaged or has sprung a refrigerant leak, it won't cool the air. Most AC units are on different electrical circuits than the air handler. Before you call the repair man, make sure the circuit breaker or fuse for the compressor hasn't tripped or blown. In most cases where the AC isn't cooling, the problem is with insufficient refrigerant.