What is a rocket mass heater? by paul wheaton   10 months ago


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I have answered the "what is a rocket mass heater?" question hundreds of times. This is my attempt to make a very short answer. Sure, there is a hundred times more info .... maybe a thousand times more info ... but the function of this video is to give a quick idea of what it is.

We start with the idea of a conventional wood stove. The fire is typically around 1000 degrees F. Heat is extracted immediately. Smoke goes up the chimney due to a thermosiphon. This design has the problem of creosote leading to chimney fires. So if you insulate the chimney, the chimney gets hot enough that the creosote burns much more often - thus reducing the risk. But the downside is that more heat leaves the house through the chimney.

We shift the design to insulate the fire box. With temperature now at 1800 degrees F, the creosote and the smoke are burned. The exhaust is mostly steam and CO2. We can now safely extract more heat. We add a stubby chimney so we can push the exhaust wherever we want. We add a mass to absorb heat. That's it. A rocket mass heater.

And then we add some pictures of pretty rocket mass heaters.

Thanks to my patreon peeps for pushing me into making videos again.


Thanks to Dan Ohmann of The Grass-fed Homestead channel:


The intro to rocket mass heaters article:

The rocket mass heater 8-DVD set (plus this page has an awesome FAQ):

The rocket mass heater workshop jamboree

Relevant stuff at permies:


music by Jimmy Pardo

Thanks to my patreon supporters:

Julia Mason
Josh Phillips
wade L
Jason Hower
Bill Crim
Chris Holly
Doug Barth
James Tutor
Mark Allen
Kelton Mitchell
David Ingraham


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