This cold has made it very difficult to maintain a comfortable temperature with my old buck stove. I haven't been using my best wood, Black locust, White oak, Black Birch, thinking I could get by with my ordinary hardwoods. Started using primariliy locust last night and what a difference. Wake up to a still very warm insert. The house is still only 62 degrees but much better than without locust! What a difference the fuel makes!