I love the rocket mass heater but the home we are getting ready to move into to house 20+ (unwed mothers and our family) is a massive 6100 square feet. It has three large living areas and bedrooms that are larger than most peoples living rooms. No- most of you wouldn't want to live in this and believe me we have never lived in such a beast!! I am hoping to heat it with rocket mass heaters )) Not just because they would save on our utility bill but they are wise for the environment. How many will I need to heat such a space? I have no idea how to calculate. I can imagine getting carried away and turning it into an oven. We will be grinding our own grains and making our own bread but let's not go overboard! I also need the best, detailed instructions on building them so as to keep all of us safe!
I say do multiple 6 inch systems. Buy the plans, worth it for one-ends up being $10 per heater for you.
I don't know where you are or how your building is insulated, but I would figure on 3-6 just based on square footage.
Depending on the floorplan, I would build one for each bedroom plus one for the living room or one along each wall if more of an open floorplan in a low heat need.
"You must be the change you want to see in the world." "First they ignore you, then they laugh at you, then they fight you, then you win." --Mahatma Gandhi
"Preach the Gospel always, and if necessary, use words." --Francis of Assisi.
"Family farms work when the whole family works the farm." -- Adam Klaus
i have a 32x30 garage/shop with 8.5 ft ceilings. I first built a regular 8 in rocket mass heater and it was very efficient but didn't have enough volume so I tore it out and built a side loading rocket with a big insulated firebox and it works well for me now. I added two pipes (1.5 in) that run along the bottom edges inside that suck air deep into the back of the firebox just as the gases go up the chimney to give hot air and ignite whatever smoke is left before it goes up and hits the barrel top. I'll post some pictures when i get a chance'. I'm leaning more and more away from firebrick and toward the molded cores; you should check out Jeremy's postings if you haven't.
a side batch loader might be safer as you can close the door and walk away from it but it takes some getting used to-- I have a primer fire-- but definitely worth it. Also, put it close to a door if possible so you don't track and drop dirt. Sounds like a good project