I have a Holmes humidifier. I noticed white dust. I now remember that I stopped using it last year for this reason. I have asthma. The dust particles interferes with my breathing. I have a Homedics air cleaner. I notice that there is a building up of grime because of this white dust. I haven't decided what kind to get. I remember liking the Kenmore console type when I was young living with my parents. This kind you use filters and a water solution. This is a difficult decision. I think a must have is a temperature and humidity gauge!