I recall last summer when we put many dollars of insulation into our house along with new doors and windows. A neighbor told me I'd never notice any difference as it would still take the same amount of wood to heat it (actually more because of a small addition. Okay.... Fast forward to this morning. Last night it got down either to zero or very close. I got up late. My wife commented that I must have got up during the night to put more wood in the stove because she had done nothing and it was so warm in this house. Well, I did have to admit that I added wood to the stove somewhere around 11:00 pm as I did not go to bed until a bit after midnight. Still, I did not add any wood to the stove until a bit after 10:00 this morning. There was still unburned wood in there! So, the Fireview kept us warm for 11 hours and still going. There is another thread going about getting your dry wood ready to burn because of some low overnight temperatures. The wood we are burning at present was cut during the winter of 2008-2009 and then was split and stacked in April of 2009. We at present are working on the wood for the year 2016-2017. This, I believe is the number one key to keeping warm in the winter. That is, good dry wood that Mother Nature has dried for you. Then, of course, comes the insulating of the house to keep the heat inside. So we have 3 things going for us: Great fuel, a fantastic stove and a well insulated house. Tis hard to beat.