My Tarm is being delivered today. Solo40. I'm looking at my wood shed and I have that warm feeling. I have 7 cords stacked seasoned, ready to go, another 5 cords split and heaped up for next year. More on the way. I'm wondering. 12 cords= 1800gal. of oil @4.50/gal.=$8,100.00 Wow, when I get done burning all that wood I will have paid off the boiler+ That's calculating 1 cord =150 gallons. What I'd like to know is what efficiencies are we talking about. The gasifiers are more efficient than regular wood stoves. Does the cord to gallon formula still hold true?