The answer to 'AC not heating' is that there are several common causes, including a thermostat issue, a problem with the heating element or compressor, or a lack of refrigerant. Symptoms may include the air blowing but not getting warm, the system not turning on at all, or the unit making unusual noises.
For minor issues like a thermostat problem, homeowners may be able to troubleshoot and fix the issue themselves. However, for more complex problems with the heating components or refrigerant levels, it's best to call in a professional HVAC technician to diagnose and repair the system properly.