I’ve surrounded our cast iron wood stove with some thermal mass: about 9 gallons of water and a couple hundred pounds of brick and concrete. This has:
- slowed the rate at which the stove warms the room & house after lighting a fire.
- extended by 6 hours or so the time during which the heat from the fire heats the house after the fire goes out
That’s all fine and good, but what has it really gained us? There’s not enough thermal mass to allow us to treat it like a Russian stove and build just one or two fires a day. From a time and effort standpoint, considering the extra labor involved in splitting kindling and building a new fire, it doesn’t make sense to let the fire go out and relight it every few hours.
So as I see it, we don’t yet have enough thermal mass to have just a couple of fires a day, and it might be hard to get enough around the stove. And if you’re not at that point, the only real benefit is that the stove/mass keeps heating the house for six hours or so after you let the fire go out. More thermal mass will further slow the rate at which the stove warms the house, but will extend further the stove/mass heating of the house after the fire goes out, and eventually you would arrive at the ideal of just one or two fires a day…probably.
There is the possibility that a cast iron or steel stove lets too much heat escape up the chimney to ever be able to adequately heat whatever thermal mass surrounds it to get down to the 1 or 2 fires/day ideal. One of the advantages of a Russian stove is that exhaust gases from the fire are channeled through masonry, capturing more of the total heat output of the fire. Surrounding a conventional iron or steel stove with thermal mass would be like building a Russian stove that had thermal mass only around the firebox — obviously much worse at capturing heat.
And so it’s still a question in my mind as to whether conventional stove with thermal mass can ever get even close to the Russian stove performance ideal.
Ending and Beginning 