I live in North Carolina and have a 6-month old house that is built to Energy Star standards. I was told it was a TIGHT construction. It has a total of 3200 square feet equally divided between two floors. Its HVAC system is divided into two, installed in the crawl space and attic.

I am interested in having an Aprilaire Whole-House humidifier installed. I've spoken with 3 contractors and all of them suggest just installing the humidifier in the crawl space. They said that even if I don't install a humidifier in the attic furnace, the humidity will still make it to the 2nd floor. Do you agree with this?

In addition, one contractor was telling me that the cheaper Aprilaire 600 (evaporative) would be sufficient but another one is telling me that I need the Aprilaire 800 (steam). Is this true?

I'm trying to avoid a steam humidifier because it has a higher maintainance cost.