My sis and bro-in-law went to a wood fired furnace. Damn near free to run and they can leave it at 75 and not care. My BIL and nephew spend the summer splitting and stacking wood so they can be nice and cozy in the winter.
I'm surprised you haven't done that yet.
That doesn't sound like "damn near free" at all. Even if you get the trees for free, wood needs to be split, stacked and seasoned, occupying space in the yard for at least a year while drying. Besides a chainsaw, anybody relying on wood for heat almost always has a log splitter which also isn't free. Between the maintenance needed, gasoline & oil there are very real costs to wood. And who wants to spend the summer splitting and stacking wood? Wood is a shit ton of work.
Regardless, if I was going to cut and split that much firewood, then I'd cut and split that much firewood, sell it for $50 a face cord, buy enough coal to last the winter, and take my wife out to dinner a couple times with the extra money I made (extra money if I purchased the coal in bulk, rather than bagged. I'm lazy enough to just get 50 pound bags & pay the extra.)
This. I chopped/stacked wood (without a splitter) too for a wood burning stove while we heated the rest of the house with gas. After countless cords of wood, I was turned off of wood completely and am seriously considering coal for my next house. It doesn't rot, can sit outside for years and insects/vermin won't be attracted to it. Id rather fill a 5 gallon pail from my coal bin and bring that inside the house than an armful of wood which tracks wood debris all over. I find it easier to shovel coal pieces into a stove than to load irregular shaped logs. Wood forms creosote in a chimney and carries risk of chimney fires, which you don't get with coal. You can even burn coal wet. Buddy of mine has a coal stove and he gets 12-36 hour burn times from one coal load, try that with wood. And coal is cheap and is mined in the USA.
Oh yeah, live in NH and thermometer is set to 67. House is typical 1920s construction with new windows and gas hot water baseboard heat.