Hi Judy

yes, one does have to keep all humidifiers and air purifiers clean and with frequent filter changes. I also wipe with bleach to kill any mold/mildew spores, and I only use filtered water in the system

we use the cool mist ultrasonics but I know that warm mist versions are also available

dont know why you would react to the cool mist system unless the equipment is still contaminated

good to see ya