There are two types of humidifiers that I have found. Cold evaporation
and heat evaporation
I own both. here are the pro/cons of each. the cold humidifier runs smooth has two settings (high low) and requires a new filter every season. the heat humidifier mists the air, also has two settings (high, Low)and requires no filter. the only down side is that unless your using filtered water you need to clean out the tray ever two weeks or so. it gets filled with mineral deposits. if you dont clean it, it smells gross. I found the heat humidifier works a little better and quicker, but they both work well. I think overall I prefer the heat humidifier just because the mist is refreshing and fun and you dont need to buy filters.