Alaska Hand fired Kodiak heating a bout 1900 sqf + basement of about a 100YO Farm House in Central MA (House burned in the early 1900 we were told, re-built to the same foot print sans the 2 fireplace that were there) We did blow in insulation 9 years ago and new windows all around about 3 years ago. Temps haven't gotten over 25 in the last 2 weeks (it did rain 1 day and got to 30) closer to 10 at night
Been using about 50-60lbs a day.
I still have the oil fired steam system on, set to 66 during the day and 63 at night. It comes on in the morning (temp drops to about 64-65 when coal stove runs low) other than that it only fires to keep the water hot in the system (have propane HWH)
Still learning the coal and I think if I move the booster fans further into the ducts (they are attached to the plenum over the stove right now) it will push more heat into the house. House temps run between 68 (where I'm comfortable, a little cooler on the 2nd floor for sleeping) and 71. Until I can maintain a 65-66 min I don't feel comfortable shutting down the oil so I guess some of my heating dollars is still going overseas