Even if you can't heat the house 100% with a stove, it can/will still take a huge bite outta your heating bill. A modern stove, even though much simpler than a wood furnace, (cheaper too!) is still pretty efficient. With a forced air furnace there are always losses in the duct work, it would be even worse in your situation...using air to transport heat is actually not very efficient. With a stove you also get the benefit of the radiant heat directly to the living area...which you would lose all that with an open basement.