What is required to maintain a whole house humidifier? And how often should maintenance be performed?
Not an expert, but generally the procedures to maintain the system would be to clean out any mineral buildup left by the water evaporating, especially in the pads or other evaporation parts, and replace any "consumable" parts as needed.
Frequency would primarily be dictated by the manufacturer's recommendations, but if nothing else, I would do at least an annual check, probably at the start of the heating season.
Should I get an active or passive whole-house humidifier?
I had to look up the models you mentioned to re-familiarize myself with the product line.
I would suggest looking into the 800. The steam humidifiers not only work better at properly humidifying your home but they also give us less call back problems.
I mostly agree with what Bo Miller answered . However most of my experience comes from the desert cities near Palm Springs CA. where adding humidifiers does help people with health issues and maintaining valuable art and furniture.
Quick question : Do you and/or your wife feel static shocks a lot ?
Just for kicks : Please let me know the model of your condenser. I want to run the numbers and see what type of system you have.
I am curious how all this works out so please keep us informed.