[mountaintimefrm]

I had a rocket mass heater for a few years and it was awesome - no smoke out the chimney, just steam. I burned sticks raked up out of my yard, pinecones, construction scraps, etc.

There have been a lot of improvements in RMH design in recent years, led largely by the RMH enthusiasts at https://permies.com/f/260/rocket-mass-heaters

IMO traditional metal wood stoves really suck compared RMHs, but they can be made better by routing the exhaust through a stratification chamber (eg a large metal container like a barrel or a old water tank; hot flue gas enters the top, cooler flue gas exits the bottom). Pretty easy to set up next to an existing wood stove, and you get a lot more heat and a lot less smoke out of an otherwise crappy stove.

[rascul]

I've always found rocket mass heaters to be quite interesting. One day I'll get around to making one. I'm in an area where I might be able to use it a couple weeks out of the year so it's not much of a priority.