The answer to 'AC blowing hot air' is that there are several common causes, including a refrigerant leak, a problem with the compressor, or a blocked or dirty air filter. Symptoms may include the air coming from the vents feeling warm or hot, the AC unit running constantly, and your energy bills increasing.
If your AC is blowing hot air, the first thing to check is the air filter. A dirty or clogged filter can restrict airflow and cause the system to work harder, leading to hot air. You can try changing the filter yourself. If that doesn't fix the issue, it's likely a more complex problem that will require a professional HVAC technician to diagnose and repair, such as a refrigerant leak or compressor failure. Attempting to fix these issues yourself can be dangerous and may void your warranty, so it's best to call in an expert.