not sure what your estimate for btu usage is but i know i have a 1 floor home of 1200 square feet On electric heat (i know that sucks) and for last night it used in the area of 12 btu per square foot averaged over 24 hours. so if you said you were using about the same average you would require 2000 x 12 btu = 24,000 btu per hour (for the next 12 hours would be) x 12 =288,000 btu to heat your home for 12 hours...now lets say your stove is 70 percent efficent..you would need another 86,400 so add them together ...374,400 btu required in the furnace....now about 6000 btu per pound of wood...374,400 divided by 6,000 = 62.3 pounds of wood for that 12 hour burn this would change if your btu need were more but you can see where i am going with this...how many pounds of wood do you burn overnight...remember the 6000 btu per pound is wood at about 20 percent moisture (considered dry) these are all just averages but shuld give you something to go by