Moist air not only helps relieve your baby's nasal congestion but it also can make for a more comforting sleep environment. When selecting a humidifier for your baby, it's best to opt for a cool-mist humidifier over a warm-mist one. Although they both accomplish the same thing, a cool-mist humidifier is safer because the steam from a warm-mist humidifier could get too warm or burn your baby if they get too close. Even an accidental spill from a warm-mist humidifier can cause burns.