Up Flow
Up flow layout with a Bypass humidifier normally located in the basement, utility closet, or attic.
Up Flow layout with a power humidifier normally located in the basement, utility closet, or attic.
Down Flow
Down Flow layout normally in homes with NO basement where the ductwork is located under the floor.
Horizontal
Horizontal layout normally located in the crawlspace or attic of the home laying on its side.