I finally got my old Reznor RA-110 110,000 btu Waste oil furnace set up in my new shop, a couple of weeks before Christmas. Shop is 30 X 32 X 12. Beside it is a circa 1939 Florence Hot Blast wood & coal stove, made in Columbus, OH. I set the WO furnace @50º, then fire up the stove when I working out there. I found out long ago, keeping the concrete floor fairly warm, makes heating the shop a lot easier.
I got this furnace just as fuel oil prices started to climb. I had a 120,000 btu fuel oil furnace in the other one, and would go through about 450 gallons of fuel oil, in an average winter. When fuel oil was .80 cents a gallon, that wasn't much of a problem, as I spent most my time puttering in the shop, and still do. The WO furnace, which I bought used, paid for itself the second year. I have several neighbors that save their oil for me, and in fact, need to go pick up 150 gallons off the neighbors son-in-law when the weather breaks. It's pretty nice having some buddy's that farm, and drive semi, and have some heavy equipment for off season income, that service their own equipment.