We have a house that has a Downdraft furnace that is original to the house, 1955, and the previous owners put on an addition and added a separate updraft furnace in the addition, 1993. is there a way or a unit out there that we could go down to 1 unit for the entire house? just to clarify, the original part of the house the ducts are run in the slab and the addition is through the attic down the walls.