Average Usage Per Day

David, any underfeed bituminous stoker, if operated properly and supplied with proper heat reflection in the firebox, can reach 85% combustion efficiency. Efficiency losses from handfiring bituminous coal are not significantly different from losses with anthracite; instead of wasting hydrocarbons as visable smoke, you're wasting carbon as CO. In a large hand-fired appliance where the fire is constantly burning especially low, with bituminous coal sooting of the heat exchanger you will lose heat transfer efficiency (that's not combustion efficiency losses, but overall efficiency), but in a stoker properly tuned, or in a hand-fired appliance that's not significantly oversized, you will get very little if any soot buildup on the heat exchange surfaces. In fact, anthracite coal generally requires a higher percentage of excess air to achieve complete combustion, and in tests on both inclined bed or underfeed stokers bituminous coals consistantly achieve better combustion efficiencies.

I'm not exactly sure about the weight, but I average 4- 5 five gallon buckets per 24/hr period. I would estimate each bucket weighs 30-40lbs. I'm heating ~1800sq/ft house, and a 672sq/ft detached garage.

Using about 40# per day here keeping house 70' days and 68' nights. I may be using a bit less but not much this year vs. past years after replacing windows and insulating, but the heat in the house is much more even now. Still have to insulate one wall in the kitchen and some more in the attic. Can't do the last wall in the kitchen until I come up with the $$ to replace the cabinets as they are built in and will be destroyed taking them out.

Comparing usage can be done with this link.
So You Want to Compare Coal Usage.
Not as popular a system as I had thought