Consider an outdoors wood burning furnace that uses your duct and fan set up to circulate the heat from the furnace to the house.I wish we had a safe place to use a wood stove being we have a lifetime supply of good oak wood plus enough pine for kindling when nice and dry. My job used to be to carry wood in at night and my little brother would go out and stack it in my arms so I could carry more at a time and get through sooner. It was usually a lot of small oak and then a few large round pieces to but on top of the bed of glowing coal at bedtime to burn until someone got up the next morning. I sure wish I had that old stove to heat my shop now.
They are very popular around here.