The answer to 'why is my central air not heating' is that there are several common causes, including a faulty thermostat, issues with the heating element, or problems with the blower motor. The most common symptom is that the air coming from the vents is not warm, or the system is not turning on at all.
Some potential solutions include checking the thermostat settings, inspecting the air filters, and ensuring the power is on. However, if the issue is with the heating element or blower motor, it's best to call a professional HVAC technician to diagnose and repair the problem. Attempting to fix these more complex issues yourself could be dangerous and may void your system's warranty.