they make two diff models
one option to attach onto the a/c ducting and controlled by such. and then 2nd option it is for non ducting/a/c and basically you will need good quality water without lots of trace /contaminate .
non a/c version, this is what I was going to get but I went diy ( kinda wish I went this route cause I have little to more room for a tout on the ground )
Shop this powerful steam humidifier with modulating output and ensures efficient, balanced moisture levels. It is perfect for large spaces and milder winters.
www.sylvane.com