Wow, good point about the addition John. Did you adjust your wood inventory at all this year based on the addition? If so, was it a "I think this sounds good" type of calculation or did you have a more structured way of doing it?
I did not do any formal figuring, especially since the addition also included replacing all the old windows with high efficiency windows, gutting most of the walls in the cabin and re-insulating with spray foam. It actually seems like between the windows and foam insulation, the wood use is not too much higher, it is just for almost the whole month of December, we have been in the single digits and low teens for highs. On the days when we have been in the 20's, the wood usage is not that much greater than it was without the addition.
I am not sure why there is such an increase in wood usage with air temps around 10 degrees F or less vs. temps in the upper teens and 20's, but it has always been way more than is seen with similar air temp differences.
-John
PS. Steve, are you concerned at all about the snow sliding off the woodshed roof and hitting your boiler?