Cool mist or warm mist humidifier — which is better?

Across the reviewers we read, cool-mist ultrasonic and evaporative models dominate because they are energy-efficient and safe around kids, while warm-mist (boiled steam) units like stainless-steel designs are praised in specialist communities for being more hygienic since boiling kills microbes. The tradeoff reviewers cite is that warm-mist units use more power and can get hot, while ultrasonic units can leave white dust if you use hard tap water.