I heat 4100 square feet total, the house is 2800 and the basement is 1300, I can turn off the ducts to the basement so I'm not heating that all the time. 34 large windows and 10 smaller ones, 8 exterior doors, most of the windows are circa 1887 single pane wavy glass but I added storm windows on all the windows, an average of 12"-15" of insulation in the attic, Wall insulation is the same as any other house of this vintage, not much can fit in there. I'm using about 80# a day on average which includes heating all my hot water, every night before I settle down I empty the ash bucket and fill the hopper. In the morning I'll check and see how much coal I used overnight, it's usually less than 50 pounds. The hopper holds 450 pounds and the ash bucket will hold ~100 pounds of ash but I don't let it get to that point, it's easier to empty the ashes when the bucket is 1/4 full, no mess, no dust, and it's light. When the outside temps are above freezing I don't use very much coal at all, less than 50# per day, when it gets down to the teens it augers much more into the boiler. I bought 6 tons, I'm hoping that will last from Oct 1st '07 through may 1st '08. I'll probably need 8 ton a year, time will tell.