The answer to 'why is my AC not heating' is that the most common causes are a malfunctioning heating element, thermostat issues, or a problem with the refrigerant. If your AC unit is not producing warm air, it could be due to a broken heating element, a thermostat that is not properly calibrated, or a refrigerant leak that is preventing the system from heating properly.
Some common symptoms include the AC blowing cool air instead of warm, the unit not turning on at all, or the thermostat not registering the correct temperature. Potential solutions include replacing the heating element, recalibrating or replacing the thermostat, or having a professional HVAC technician check for and fix any refrigerant leaks.