Air conditioner, humidifier, and purifier. A secret to the effectiveness of an air conditioner is water. The water evaporation process, enhanced by the airflow from the fan, creates a cool, pleasant mist. The water vapor is pushed out along with the air by the built-in fan from the humidifier. As a result, the cool air produced by the WT10 serves a dual purpose: it helps you endure the heat and increases the humidity in the room.