I had my 1st coal fire in the new installed furnace in basement. The weather was cool here on Monday 8-25-08 in the 40's @ night. Warmed up nice during the day but cool at night. Filled it up on monday evening a bag stove and a half a bag of nut and left bottom damper opened 2 turns kept fire nice all night and was 73 inside in the morning. I shook it down next morning and kept it going. Long story cut short I was able to keep it going until thursday am on the same load of coal by shaking it down in the morning and evenings and still have some coal left in the firebox. I seem to be getting a lot of heat off of furnace in basement which I guess is ok as it makes the floors in dining room and kitchen seem like raidiant heat. I dont want to make to many changes until it gets good and cold to see how good everything is going to work. My furnace is an addon unit that has a 12 inch round duct with back draft damper that takes heat into plenum on oil furnace and then through duct work. The big blower on the oil furnace does not come on but the coal furnace is able to push heat through the duct with out any issues. I may play around and see if i can get the big blower to come on and see if it will push better heat that way.