Just an observation, but most of all that's out there are "cool mist" ultrasonic units - that aerosolize whatever contaminants are present in tap water. Coincide that with the shortage of bottled distilled water. Can't find any anywhere... Mostly a rant, but also a concern. Most folks filter tap water, but what's that matter if you're ingesting it thru your lungs from running shoddy tap water thru a chynese made humidifier?