We heat exclusively and cook almost exclusively with wood--not because we have to, but because we want to. I have a stove in the basement and a masonry heater on the 1st floor. Granted, I have to fire them both when temps are below zero
to keep the place above 70 in most rooms, but I am also aware that we would probably make it if we'd put an extra blanket (or cat) on the bed and let the house dip into the 60's or even 50's. Now if I really had to worry about heating with wood efficiently, I would have designed a house with lower ceilings and smaller rooms, but thanks to modern insulation, we are in pretty good shape anyway. If the power went down for an extended period, things would be more complicated, but we have a stream running through the property that has potable water, so we wouldn't dry up and we'd still be able to flush as needed
. At any rare we would abide.