A lot depends upon the "air flow" in your house. How well does the existing heat spread throughout the house? What rooms are directly above either option, and how much time do you spend in them?
And on your use of each room. How much time do you spend in each?
Generally, the more centrally located the better. The heat can then spread out from there.
My wood stove is in my kitchen/dining room. It is the central room, with the living room winged off of one side, and the bedroom off of the other. The three rooms upstairs I generally just keep shut off. But that wood stove is my primary heat source - in an old farm house with almost no insulation and windows that the wind rattles on the other side of the house as it goes back outside! Occasionally I will put a fan in the doorway to the living room to help ... spread the heat. And I prefer to sleep in a cooler room. So it all works out pretty well for me.
There is a chimney in the living room that I could use. Over the years I have hooked up a wood stove in there, but usually do not. The extra heat gained isn't really worth the space necessary for the stove, or the effort to keep it stoked up. I just keep my wool blankie by my chair and wrap up as necessary. Of course, once I do get wrapped up, then the kits start ... piling on! It's OK, at least until I have to move and get all those "dirty looks" for disturbing them!
Just a few humble thoughts to share. Take them as such.
Mikey - that grumpy ol' German blacksmith out in the Hinterlands
