Using a humidifier with a 12 month old?

I am looking into buying a new humidifier for my sons bedroom. He just turned a year old. He has a bit of a stuffy nose so I am hoping this will help relief it so he can sleep better. Does it matter if it is a cool mist or a warm mist humidifier? Isn't it just a safety thing so the cool mist is recommended for children since the water is never heated? Does one work better then the other?