Hey everyone. This is my first post on this site after Google keeps directing ALL my questions to you and finally signing up.
Although this thread is more than a year old, I thought I would share current personal experience as to why a 10:1 efficiency would be somewhat in the realm of reality. I have attached 2 pics. One of the fireplace and the second of the "super efficient" wood stove my family have been using for the past 5 or 6 years.
This is supposed to be a decorative stove that my grandfather had installed years ago, with my uncles blessing. Well, now that I have moved in to help my grandmother after my grandfather has left us and my uncle no longer lives here, this is the LAST season this wood stove will be in the house. Come hell or high water it WILL be replaced with a much more efficient and LEGAL wood stove. Unfortunately my grandmother is too old school to convince her of anything else radically different. This thing has scared me for as long as it's been here. But back to the reason I posted this.
We have forced gas heat in the house, about 1400 square feet and the ducting wasn't well maintained. The thermostat in the house is kept at a minimum of 66 to 68 degrees F so at night the house doesn't get freezing if we don't have a fire in the wood stove. Now, that wood stove will heat the whole house really well with a good box fan blowing around it, but it will DEVOUR the wood and we have to keep feeding it every hour or so. So even with a gas furnace keeping the house at a somewhat comfortable ~67 degrees, we can go through 3 to 4 cords of wood a season. And when we fire it up we smoke out a lot of the neighbors. I hate the damned thing because as an engineer I can see the inefficiency pouring out of the chimney. As well as my uncle "teaching" my grandmother that keeping a smoldering 'indian fire' and sitting next to it is the best way to keep warm. Drives me absolutely insane.
So in conclusion, if people, which are quite a few around here, use this type of wood stove to get supplemental heat, imagine if we had an actual thermal mass wall with a 1 or 2 time a day burn. We would probably only go through 1 cord a season, and save hundreds in gas bills.
EDIT: Oh, and we live just outside of Portland, Oregon in the Pacific Northwest, near Mt. hood at an upper elevation, for geographical reference.
