The answer to 'why is my humidifier not heating' is that there could be several common causes, such as a malfunctioning heating element, a thermostat issue, or a problem with the water supply. Symptoms may include the humidifier not producing steam or the water not getting hot enough.
Some potential solutions include checking the heating element for any damage or buildup, ensuring the thermostat is set correctly, and verifying the water supply is working properly. If you're not comfortable troubleshooting the issue yourself, it's best to call a professional HVAC technician to diagnose and repair the problem.