I have no idea about the numbers involved. I only know the end results.
This building I was talking about went from $4,500 a season in heating to less than $500. That's all I know.
And the place I work at ( http://www.woodmaster.com ) makes a 3300 model (for up to 2,500 sq ft), a 4400 model (up to 5,000 sq ft), a 5500 model (up to 7,500 sq ft) and a 6500 model (up to 10,000 sq ft). All of those are using wood for fuel. They also make the AFS1100 which is made for corn, wood pellet, or paper pellet. It is physically the same size as the 3300, but the firebox is half the size. The rest of the room is used for the auger mechanisms.
Oh, and the recommended sq footage for the AFS 1100 I believe is 6,500 sq ft or more as anything less and the corn will actually go out waiting on the buildings extracting enough heat from the water to make engaging the blowers worthwhile. The 6,500 sq ft recommendation is a MINIMUM, not maximum. We use two of the AFS 1100's and one MF6500 to heat the main shop (75 X 300), the storage shed (100 X 200) and the warranty shop (60 X 100). None of them are anything more than a sheetmetal pole barn. And the corn burners? They share a small silo that I would say is about the size of my 1000 gallon septic tank, maybe a little bigger. So let's say 1,500 gallons to be generous. No idea what that equals in pounds. It was filled in October of 2004 and is still at least 1/3 full.....
Oh, and as for fuel in the 6500? We use all the pallets that our supplies are delivered on. On average about 6-10 pallets a day. Between the three stoves it maintains the in-floor radiant hot water at 155 deg F. Oh, and the five heat exchangers it all goes through to heat all the buildings potable hot water, too. So we have instant-on hot water at every faucet.