I tried the traditional kind - steam generating - and they put a lot of heat out along with the humidity. Also quite expensive to run. I now have one of the 'ultrasonic' or fog type humidifiers. It is cheaper to operate, but it does put out more of the minerals that are usually eliminated by the heating process in traditional humidifiers. I solved that by using distilled water. The one I have has a built in humidity sensor, so it turns itself on and off as needed.. and has different 'speeds'. It was a rather high priced one, though. All in all, if you have the interest and money to invest in a long term humidifier, I would recommend an ultrasonic.