What are humidifiers categorized into?

Humidifiers are indeed categorized into active and passive types based on their operational principles and the mechanisms by which they deliver moisture into the air or to a gas stream.

Active humidifiers utilize an external energy source to generate moisture, typically through methods such as ultrasonic vibrations or heating elements, which effectively produce vapor or mist. These devices actively increase the humidity levels either by creating a fine mist or by heating water to produce steam.

In contrast, passive humidifiers rely on the natural processes of evaporation and typically use a wick or similar media that absorbs water, allowing it to evaporate into the airflow without any mechanical assistance. These devices do not require additional energy input to operate, making them simpler and often more cost-effective.

The other categorizations mentioned—high-flow and low-flow, cool and warm, and mist and vapor—refer to specific functionalities or characteristics of humidifiers but do not encompass the fundamental operational classification of active versus passive. For instance, high-flow and low-flow describe the volume of gas carried by the humidifier rather than the method of humidification itself, which is not applicable to the main categories under consideration.