Smallest "Shelter" with rocket mass/or wood heat?

Hello, I was curious how small of a shelter one can build that can incorporate a rocket mass or wood heat into the set up? Has anyone gone so small of a foot print to have something like a stock tank used as a shelter but that could also keep ones (maybe two ) people comfortable in the winter with very low wood usage? I have a one green world order coming after I get that planted I'd like to look more into some options I can add into this mostly suburban property (and then possibly another more remote location)


Thank you

Welcome to Permies James!

I actually was thinking about a very similar question to this yesterday! I have a small village property but I want to tinker with the whole rocket mass heater contraption but on a smaller scale.

I hope someone will have an answer!

My cabin is approximately, 127sf. and is heated with a vent-less ODS equipped radiant propane heater. Some 7 years ago, I seriously pondered a RMH (Rocket mass heater), but shelved the idea. Why?...

1.)  I'm solo (except for a 10 pound, 4-legged, furry companion), and well-into senior status.
2.)  While I live near an abundant wood source, I'd prefer to not spend my precious time driving, hauling, cutting, splitting and storing wood. Not to mention, I don't have dry outside storage area.
3.)  I own a 100 gallon propane tank (easily 7-8 mo supply) - and free delivery.  
3.)  Continuous feeding of wood throughout the day, irks me. And I prefer 6-8 hours of uninterrupted sleep.... and waking up to a warm cabin.
4.)  I have relatives I occasionally visit 5.5 hours away - 2 maybe 3 days duration away from home. Really nice to be greeted with a warm home upon returning - especially when temps drop into the 20's - and not be needlessly worrying about loosing a cabin full of temperature sensitive perishables.

There are several very small shelters with very small rocket mass heaters at Wheaton Labs. The one I remember for needing to be super small was this one: https://permies.com/t/166852/rocket-mass-heater-bartell-bunkhouse#1323255
Scroll up and down from that link to see more about the location and sizes of things.

Just how large/small is the stock tank you're talking about? I'm pretty sure I've read about RMH's in shelters as small as 10' by 10', but one would have to be *very* careful with air gaps to make sure the hot cycles didn't increase the flammability of nearby materials.

The huge benefit of an RMH is that the mass keeps giving warmth long after the fire is safely out. There are mini-wood stoves out there, but an hour after the stove is out, if the heat wasn't somehow put through some mass, the heat will be gone. The one that was in the Tepee at Wheaton Labs was likely a larger space than what you're describing, but part of the mass was the bed platform, so the occupants were kept warm all night.

Of course the flip side is that mass takes a long time to warm up, so if your shelter is only used occasionally, by the time you have it warmed through, you may be gone again. What makes an RMH efficient, is that the heat that a conventional wood stove sends up the chimney, gets absorbed into the mass. A rocket stove can get complete combustion, which is helpful for the environment, but it still won't hold heat if some of that energy isn't used to heat a mass.

Welcome to the forum!

Matt Walker's Walker Stove is fairly compact and could fit into a small living space and be used for both cooking and heating a small space:

https://permies.com/t/72460/Walker-Cook-Stove-Plans

Here are some threads where others have contemplated similar ideas:

https://permies.com/t/33908/small-RMH

https://permies.com/t/40/5505/smallest-rocket-mass-heater

https://permies.com/t/5505/smallest-rocket-mass-heater

A rocket stove could be made out of small cans and then a mass could be added.

https://permies.com/t/170020/Build-rocket-stove-food-tins

wow thank you for the replies!!!

(60 percent off recent order planted.... back to the grind )

I will be reading and looking at the links. THANK YOU ! !

Why not put the 'cart before the horse ' and consider the smallest dwelling you could create that is comfortable and think about heating it.
I am sure I have read a topic about a small dwelling at the Wheaton labs.

yes thank you. Is there a link to what you are referring to? I got some more plants in so that will take my time this weekend, but I would look into it !

Thank you