Building new open concept home like a barn structure/post and beam interior. The basement is connected to first floor with large open stairway. 2nd floor is open to the first. Does GEOThermal unit work better/more efficiently as just 1 zone or can we get away with 2 or 3 zones? We initially wanted a zone on each floor, but have heard that geothermal units/pumps work much more efficiently on a single zone. Any thoughts/opinions would be greatly appreciated! In addition, would there be a big cost savings if we went from a 3 zone to a 1 zone system?