I am interested in switching to geothermal for my heating and AC, but live in an old house (built 1928) with a natural gas/hot water radiators system. Geothermal will require installing duct work for the forced air heating. We have some ducts, since we installed central AC, but not enough for heating. I am told that geothermal cannot produce enough heat for hot water radiators, but that the technology is improving. Does anybody have any sense of when it will be able to work with a heating system such as ours? I know this is difficult to predict, and nobody out there has a crystal ball, but is this something that seems to be a year or two away, or is it over the horizon? My current systems work fine for now so I could wait.