The answer to 'humidifier blowing cold air' is that the humidifier may not be functioning properly. This could be due to a few common causes, such as a malfunctioning heating element, a thermostat issue, or a problem with the humidifier's fan. When a humidifier is blowing cold air, it typically indicates that the unit is not able to effectively heat and humidify the air as it should.
In many cases, troubleshooting and resolving a humidifier blowing cold air can be a DIY task, especially if the issue is with a simple component like a thermostat or fan. However, if the problem persists or you're unsure of the root cause, it's best to call in a professional HVAC technician to diagnose and repair the issue. They will have the expertise and tools necessary to properly inspect the humidifier and get it functioning properly again.