paul wheaton
Full Member
Posts: 53
Joined: Thu Apr 09, 2009 8:32 pm

Heat your home with 5 to 10 times less wood

With encouragement from I others, I bring you some stuff that I think is pretty huge ...

First .... consider ... modern fireplaces and wood stoves send 80% or more of the heat right up the chimney. Wouldn't it be nice to send only 2% to 5% of the heat up the chimney?

Next .... some modern wood heaters claim to be 90+ % efficient - referring to how completely they burn - thus how, little smoke they let out. Wouldn't it be nice to have that value closer to 99.9%? 99.99%?

This technique burns wood a completely different way. And you really have to think about several things in a different way. Most of the heat we are used to is heated air. But if you accept that as just one way to heat and open yourself to radiant heat and conductive heat as well ....

I'm getting ahead of myself.

And now for some "how does it work" info ...

Here is my own feeble attempt at drawing how this works:


The key is the combustion chamber.

Since it is insulated, it gets very hot. And that makes for a very powerful draw. So much draw, that you hear a sort of rocket-y sound. Hence, the term "rocket mass heater". Since the draw is so strong, no smoke escapes the wood feed. And, since the draw is so strong, you can push the exhaust for up to 100 feet.

Most of these will push the exhaust to a bench with a lot of mass. The mass then slowly warms and slowly releases heat over the next few days. Some people will route the exhaust through a floor.

It is my obnoxious opinion that the design is absolutely brilliant!

And ... then there is the whole space of cook stoves .... :)
Last edited by paul wheaton on Thu Sep 24, 2009 5:22 pm, edited 3 times in total.

sweet thunder
Senior Member
Posts: 210
Joined: Thu Apr 02, 2009 5:43 pm
Location: Eureka, CA

Wow, that's really cool. I've seen the soapstone masonry fireplaces that are similar, but they're vertical. This style makes a lot of sense, though, with all that horizontal heating surface.
Probably not the kind of thing I could easily retrofit into my existing home, though, huh?

paul wheaton
Full Member
Posts: 53
Joined: Thu Apr 09, 2009 8:32 pm

At the workshop, there was a guy whose job was nothing but mass heaters - mostly using the massive soapstone stuff. He said the minimum cost of one of those is $10,000.

You could do the bench as soapstone.

You could replace the barrel with something welded that looked much nicer.

What is the floor like in your home?

Return to “Permaculture Forum”