The answer to 'central air not heating' is that there are several common causes, including a malfunctioning thermostat, issues with the air compressor or refrigerant levels, and problems with the air ducts or blower fan. Symptoms may include the air not blowing out of the vents, the system not turning on, or the air not getting warm enough.
Some potential solutions include checking the thermostat settings, cleaning or replacing the air filters, and inspecting the outdoor compressor unit for any damage or obstructions. However, if the issue persists or you're not comfortable troubleshooting the system, it's best to call a professional HVAC technician to diagnose and repair the problem.