For anyone interested in fine tuning their firewood needs, or just learning more about their wood heating system, what follows may be a methodology that is useful and informative. During the 2nd half of November I logged outside temperature, which has allowed me to calculate Degree Days (based on base temperature of 60F). I also maintained constant my radiant floor temperature at 63-64F, which resulted in inside shop air temperature of 58-64F, and I weighed the wood burned, including kindling. All calculations are based on the assumption that my wood had effective heat value of 6,050 btu/lb (20% MC and 400F flue temp). The shop is 1500 sq ft, R19 nominal walls and R39 nominal ceiling, fairly typical for much newer construction. During the test period Nov 17pm - Dec 1 am (14.54 days actual): Degree Days (base 60) = 558 Wood burned = 765 lbs (1,288 lbs burned during the entire month) Wood heat value = 4,628,250 btu Btuh = 13,261 Wood/hr = 2.2 lbs (weight a small log to see how small this actually is) Wood/day = 53 lbs Btu/Degree Day = 8,294 Wood/Degree Day = 1.37 lbs Firewood burned during this time was all jack pine, which seasoned (20%) typically weighs 2,670 lbs/cord. Wood burned for whole month: 0.48 cords Wood burned during data period: 0.29 cords Annual normal Degree Days for a reporting station 5 miles from where I live are 9,017 (recalculated to base 60 from base 65). If 1.37 lbs wood/Degree Day, then my annual wood needs are 12,353 lbs, which is, for example: Aspen: 5.38 cords Jack Pine: 4.63 cords Cherry: 3.96 cords Red Oak: 3.39 cords White Ash: 3.35 cords White Oak: 3.08 cords Hickory: 2.85 cords Besides Jack Pine, Aspen is the other primary wood I burn, so right now it looks like I will need about 5 cords of firewood per typical year, and my goal is to always burn 2nd year wood, so I will need 10 cords on hand for the start of each heating season. These numbers, and other data I collected, can be worked to provide other interesting information, but this seemed most useful. Nov - Mar are the normal cold months where I live, and I hope to continue to log data to better understand how btuh changes with differences in the dT between inside and outside temp, and therefore how actual wood usage/needs may vary from this initial calculation.