Hey all you crazy permies! I need to pick some knowledgeable brains, and I know they're hiding in here!
My wife and I have a 1152sf (32x36') stick-frame, truss-roofed, single story above-ground house on a slab (gag, but it's good enough for now) on our little 'stead. It's a pretty open floor plan, save for two bedrooms at the south end of the house. We're heating the place with a 1980s Earth Stove, your standard plate steel, window in front, blower shroud over the back wood stove. Smallish firebox, the sticks need to be 18" or less to fit, and it won't hold a burn overnight unless we make a HUGE mess of coals. Also, since we're using the chimney the previous owners installed, the stove is in the north corner of the house- not a bad placement, but it takes a while for heat to reach the south corner. We're fortunate in that the PO's only drywalled the bedroom walls up to eight feet (the outside walls are 10'), which allows heat to go over them and down into the two enclosed bedrooms... eventually.
I'm considering building a mass heater, and can't decide between a RMH and a Russian Stove. Both of them operate on the idea that one can extract almost all available heat from a small mass of wood, and retain it to radiantly heat one's living space rather than expending it up the chimney. The RMH, as we know, uses the rockety reburn chamber to make a blast furnace effect, and also to provide a workable cooktop, before routing the remaining heat through the cob bench to extract the remainder of the heat prior to its exit from the home. The RS, on the other hand, has no work surface (although some intrepid souls have incorporated small ovens into the flue path), but puts all available heat into the bricks, and routes the flue through an up-and-down zigzag path to extend the time (and space) of the flue inside the domicile, to keep all available heat indoors rather than going up the chimney. It also has a 3-4' horizontal burn chamber to allow the use of long branches rather than requiring the repeated feeding of small bundles of sticks.
The pros and cons, as I've figured them, are as follows:
RMH Pros: Ease of construction, low cost of parts
RMH Cons: Increased work of mixing and forming the cob, the radiant heat source is limited to an outside wall due to the horizontal flue. Also, since RMH are not known to perform well with vertical flues, this obviates its placement anywhere but along an outside wall, where some heat will be lost.
RS Pros: Centralized, fully-radiant heat source, less feeding required, vertical flue allows placement anywhere in the living space.
RS Cons: Expensive (unless one is adept at scavenging bricks, incl. firebrick), labor-intensive construction, takes up valuable center-floor space.
Given these, plus whatever input you may have (and I certainly welcome), which of these would work best? I'm leaning toward the Russian Stove, because I like the idea of keeping the heating mass as close to the center of the house as possible. I also don't relish the idea of sleeping on cob, although with a decent mat I'll try anything.