Which is Better: Warm Mist or Cool Mist? 

The major difference is that a Warm Mist Humidifier is heating the water to produce steam vapour. Cool Mist Humidifiers use an Ultrasonic Nebulizer that vibrates at a very high frequency to produce an extra fine water mist. When it comes to humidifying a room, there is not much of a difference between the two types - both are equally effective. However, paediatricians and parents alike recommend Cool Mist Humidifiers for babies and children because there is no heating element, which could be a safety risk for a child. Cool Mist Humidifiers can also save money on energy costs.