So, my primary collection is vacuum cleaners, but I also have a small humidifier collection, wonder if anyone else on here finds these interesting. There are actually a few different technologies that are used by these appliances. I'm not really a fan of the warm mist models, I prefer the cool mist variety. There are three different technologies that I've seen with these. I think the first type is called evaporative, I have one of those made by honeywell, they use a wick filter and the fan blows air through it, these work well but are kind of loud because of the large fan. The second kind is not seen much anymore but I think they are kind of neat. I think they are known as impeller humidifiers. I think they still use a fan, but not sure. A plastic tube sits in the water and spins, and it moves the water through what looks like a bunch of teeth, probably a defuser or something. I have a vicks model 4500 that works this way, I actually like the sound these produce. When I was growing up, there was a really popular brand of these called hankscraft. Then there are ultrasonic models, I have several of those, they are really quiet, I guess they use ultrasonic sound waves to break up the water in to a mist. Wondering if anyone else has played with any humidifiers and if so, what are your favorite ones?