Daniel Truax

Jim, I went from a steel box wood stove to a RMH 8". I dropped from burning 18 face cord a year to 9 face cord. It was worth it for me, I turned 1/2 of my wood storage into places to park my tools.

I live in NYS right next to lake Ontario. This is my 3rd winter season of heating with it.

Here is my stove so far...

My middle name is overbuilt, but then again 2 ton on wood cut in 1860 may require a little support to keep tile from cracking mortar and tile...

Your Floor sounds similar to mine this is what I did to support all that weight, I only had room for 2 tons.

RMH on wooden floor...

RMH ash drop...

Closed...


Open and drained...


Ash clean stove and no mess in the living room...


Building an RMH on a suspending wood floor was a pain in the ass, but the ash drop alone was almost worth it...

And link to whole stove My stove so far...

This is how I did mine, what they describe is similar...

My RMH

A 8" system can have twice the gas flow a 6" system can. So an 8" system can eat wood twice as fast as an 6" and put out about twice the BTUs. In the same home with the same mass you would have to light a fire and burn roughly twice as long with an 6" system.

A 8" in a small house would be burned maybe not often enough, so the mass gets too cold and you get condensation. A 6" is a too big house would have to be run too often and could be a pain in the ass. In some medium sized/insulated houses either system could work.

Lots of free 6" piping to be found, used 8' piping is harder to come by.

I almost wish I used a 6" system since I could have gotten more mass in my couch (limited space) that way.

I have burned a shitton of cardboard in my RMH, it burns clean and hot, I was doing it mostly to get rid of it. The downside is that one day of burning cardboard produced as much ash as a week of burning hardwood. Glad my RMH dumps its ashes into a can in my basement!

A little ground wind problem maybe, try adding 6 foot exhaust chimney?

Take some of your pink insulation out, light up some incense. If the incense smoke it pulled out of the house then your build is wrong on the inside. If the incense smoke is pushed back inside then you need some kind of external chimney.

In all the rocket stove u-tube videos I have seen I don’t think any of them exhausted above the roof. I guess I could at least try hooking on a vertical 6 foot flue pipe on to where the flue exits the home to see if that works. That would be easy enough.

I had the SAME EXACT problem as you, for me the solution was hooking it up to an external chimney and all my problems went away. I had outside positive pressure fighting RHM positive pressure.

See my pics My build

Your best bet is to cut off your version of the downcomer and take what's left insulate it and put a big barrel over it, and connect it into your mass pipe and see if it works...

Your issues are why Ernie doesn't like to comment on threads like these...