RH/RMH sq ft size

I live in a house, the part that I live in and actually heat is around 200 sq feet.  Total house size is only 468 sq feet.  The rest of the house is junk storage and outside access...pretty much cluttered space.  Is a rocket heater/rocket mass heater too big for such a small space.  I can't for the life of me figure out how I could keep from sweltering my butt out of the house if I put one in my house.  I had been using propane for quite a few years until I shrank the living space down to around 50 sq ft and started heating it with a 1000 watt electric heater.  Prior to that when I was living in the full 200 sq ft I was only using 15Kbtu setting part time on the ventless propane heater I used to the heat the house.  I have seen one post about heating 26Kbtu and I never used the heater setting that high, even on the coldest of days here in central/northern New England.  Given the current geopolitical situation I would like to get away from both propane and electricity but I don't really know of anything else that would make any kind of sense to try to use.  About a year ago I started seeing the rocket stove/RMHs being talked about and have thought about the idea but haven't did any kind of playing around with them yet.

What is the structure of the house? Is there a slab, crawl space, basement?

I would suggest that a 6" RMH with a small half-barrel bell bench (maybe 3' x 8' total including combustion core) would give you comfortable, reliable heat. As for overheating, the beauty of the RMH is that you can make a fire for only as long as needed to give the mass sufficient heat, then let it coast. At the extreme, you could fire it for one hour a day and let the mass simmer along giving off warmth for the next 23 hours.

I have the same question!  I'm living in a 200 sq. ft. "yome" which is insulated canvas and round and sits on a wooden deck.  There is an opening for a stove pipe.  And we generate plenty of small wood on this small fruit farm.  Can one make a RMH small enough for this Northern California, not too cold place?  The owner is concerned about emissions and likes the RMH for that.  Could it be really easy as I'm more of a plant person than a builder......

Glenn Herbert wrote:What is the structure of the house? Is there a slab, crawl space, basement?

Crawl space, older style cottage camp with 7-8 foot ceiling in the living space and even smaller in the entryway, down to 6 foot ceiling height at the front door.  It's definitely not airtight so I'm too worried about air circulation.  I was mostly thinking along the lines of how do you size it appropiately so you can warm the house up 'slowly' while still getting the mass heated up so you can then use the mass later...versus heating the house up fast and not having even started to heat up the mass(now you shut down the heater but you have no radiated heat coming off the mass since it didn't have any kind of a chance to heat up yet.  After some of the reading I did last night it helped me come up with a ton of questions which I think I know the answers to but I will ask the one big one separately from this post.  It would make the mass side of the heater much easier to work with but just exactly what could I get away with.  That's for another post.

I'm surprised to hear you say 6 inch wouldn't be too much. . Granted I was reading one of the old posts last night/this morning where the guy was using 3 or 3.5 inch and he was only getting 90-100 degrees out.

For the standard J-tube RMH core, 6" is the smallest size that is easy to build and have it work reliably. 4" systems are finicky and considered an advanced build. Unless you are extremely cramped and have a very small heating load, it's much simpler to go with 6". Even a good 4" system will have a considerably shorter flywheel effect, meaning more frequent fires are needed.

Re your concern of overheating the house while getting the mass charged up, I would suggest a small barrel (35 gallon or so) with a layer of cob around part of it. Leave the top bare (and hopefully have a removable top for maintenance) and start with bare sides, then as you experience cold weather, you will find a balance between the quantity of fast radiating sides and cob-covered sides that works best for you.