OK, I apologize for that..I thought I remembered that some questions went unanswered in other threads. Maybe my memory fails me, again? Darn Old-Timer's disease.
I'll have to go back and look..
Anyway, I guess the lower level isn't sunk all the way into the ground and you have a pretty big opening from the lower stove level to the next level? If so, that should allow heat to move easily and heating from down there will be accomplished without some of the problems we read about with a true basement, narrow door etc. What is the sq. footage on each level?