My neighbor has an older home (1920s). The supply ducts are located on the inside walls, and returns on the outside walls. From my inspections, there is one return and one supply in each room, including the kitchen. Each is a 9" metal duct.
My question is, would it be possible to reverse the supply and returns, and would this improve heating? Also, there are no dampers. It would be possible to add dampers to each supply in order to balance the system a little better.
Any advice would be appreciated.