For their safety, always use cool-mist humidifiers for children. Hot water or steam from a warm-mist humidifier or steam vaporizer can burn a child if he or she gets too close. In the event of a spill, hot water might also burn.
Humidifiers add moisture to the air, which helps ease coughing and congestion due to a cold. Warm-mist and cool-mist humidifiers are equally effective in humidifying the air. Also, by the time the water vapor reaches your child's lower airways, it's the same temperature regardless of whether it started out warm or cool.
Another benefit of cool-mist humidifiers is cost. Cool-mist humidifiers are less expensive than are warm-mist humidifiers because you're not paying for the heating element. You may also pay less in energy costs. If you use a humidifier, be sure to keep it clean to prevent the growth of bacteria and molds. Wiping down the humidifier daily with a 10 percent bleach solution — 9 parts water to 1 part bleach — is one way to safely keep it clean.