I have no experience with them but we did talk a little about it towards the bottom of this thread Cost Of A Cord Of Wood
Hey thats my post
I love the thing. I had a chimney cleaner come yesterday and he rant and raved about it, so did my house inspector when I bought the house. The locals said "You bought the house with that russian fireplace, your going to love that thing.".
The only thing mine needs to improve it is door vents and more clean out ports. These stoves are amazing.
I burn an arm full of split dry (<20%) hardwood with the draft full open and door open a hair (that increases the speed of the air thru it). I use just a little piece of a fire starter. Within 1.5 hours, the fire is out and its just coals. I then use a garden hoe to push the coals to the rear, close the door, and close draft so its only 1/2 an inch open. That traps the heat in the stove.
Assume I am starting this when the brick isn't warm.. it takes about 3 hours for them to start to feel warm. In about 8 hours its almost too hot to touch. Now that was the morning fire, I start the second fire at night say around 6 p.m. Then its peak heat output is in the middle of the night.
These stoves go against everything you would assume. The point is to have a short, HOT, fire that burns efficiently. Mine has been used 30 years and the cleaner yesterday said there was NO creosote buildup. DRY hardwood is a must and so are short hot fires.
The bricks trap the heat and emit it long after the fire is out. IMO, this is also safer than a normal wood stove.
The biggest perk of all is that the firewood consumption is a HUGE amount less than a normal wood stove. Normal wood stoves shoot most their heat out the chimney. MAsonary stoves are super efficient and also provide a more even heat.
Certain masonary stoves are better than others, designs and what not. And of course some cost alot more than others. I am told mine works great until it gets into the negatives outside, then it needs some help, and thats where the coal stove comes in.
I have been reading up on these alot and I seen one design that uses pellets! It traps the heat from a burn of pellets!