I have a medium sized wood burner to heat my home in the winter (all two weeks of it). A good return on the dollar. I ran a fresh air line under the slab before we poured the concrete and it is under the stove and out of sight. Made in Finland, I figure them fellas know how to keep warm and it does the trick for us.Ever consider a wood stove that sits on the hearth smack dab up against the opening of the old fireplace and then run a stainless steel flue pipe up thru the old chimney with a new cap on top.
My neighbor did a retro on his old fireplace and was amazed at how efficient they are and keeps the house warmer and not as drafty as the old fireplace was.