I have had the opposite experience. I live in VT, and a humidifier is a real need. I used to use an ultrasonic device because, basically, that is what stores

I have had the opposite experience. I live in VT, and a humidifier is a real need. I used to use an ultrasonic device because, basically, that is what stores near me had available. But I noticed that every winter I got bronchitis. I remembered that years ago I read in Consumers Reports that these can cause a reaction because they can break particles apart. (I remember it saying that it can break apart virus particles, but I'm not sure. I'm also not sure if that is correct.) Based on that dim memory, I bought a Boneco AIR-O-SWISS Warm Mist Steam Humidifier S450. It has faults, and is expensive. But I don't get annual bronchitis any more. So we use that.