10 Huge reasons you should build a rocket mass heater.

cardboard and paper waste is no longer a waste

lowest carbon footprint

This heating solution is really bad for people who don't want to be care free and toasty.

Built one here in Cornwall, the furnace was a "Gamera" and a 12ft cob bench. Me and the wife made it, we are about the furthest away from calling ourselves engineers, we just had blind faith.
It works so well, boils a kettle quicker than an electric kettle and when the mass finally gets heated, last for hours.
A fantastic system, cannot recommend them highly enough.
PS....got a great "cob" supplier here in Cornwall

This has been on my list for my cabin from the start. I'm getting on in age, and the effort of hauling and splitting large log rounds will not be sustainable for me, long term. I can easily find all the fuel I need from forestry service slash piles, nearly free for the taking. A five cord wood permit is a few dollars, and all that they ask is to not leave a mess behind. One thing I've seen complaints about is the visuals of the barrel. Its very easy to have a metal shop roll a sheet of decorative perforated metal into a cylinder you can drop over the main drum and you have a very attractive heater that won't detract from the rooms aethetics at all. Also if you plan your heat bank dimentions correctly, a couple of baby crib mattresses make excellent cushions, very easy to sew covers for.

I'm convinced, I've bought the book, I have a couple of fresh oil drums, but I don't have a source of clay soil for the cob to make the bench. Our soil is just very, very stony, Yes, do have plenty of rock and stone to put in the thermal mass, but any recommendations for the clay component?

Im think of a design to 3d model which would be a castable hybrid of a rocket mass heater and a tesla valve, the issue is what to cast it with, sugar water and a bit of nitric acid forms a very insulating heat resistant material when baked although there most be an easier diy refractory cement to try

A reducing tesla valve in the mass (bench) and opposite at the intake should give the exhaust more time to heat the mass and the latter valve should prevent the expected back draft , hoping to book a stay with you sometime to get your opinion on that and so much more

God that giant stone sofas in the wrong place.. lets move it.. (j/k)

Here's no.11

Its better in terms of particulate pollution because rocket burner has such a hot burn chamber, it combusts all the fuel including smoke, a well running rocket burner should only produce gas as a by product. This means your chimney should be clean, or at least need cleaning much much less. Apart from start up, there should be no smoke.

18 THOUSAND pounds for a heating pump? I assume you misspoke and meant 18 hundred pounds? (the super fancy water-air heating systems should last a lot longer than 10 years, even the pump I believe)

Awsome job, those who never experienced a rmh will never fully understand. I built one about 5 years ago in my garage at last house, the same shop and size i was burning 3 cords of very well seasoned hard wood before. After
1/2 cord of the same wood. Such a difference it was amazing, biggest thing i loved was the warm bench, i fell asleep more then a few things sitting on it for a "break". I had a J tube style, it probalby cost me more tinkering with it then the wood savings was as I kept making fire box design changes experimenting. I got half a batch box core done before selling the place and took the core with me to some day build another one. Absolutly amazing heat, let alone the lack of smoke that was a big one. So much more consitant heat too vs a box stove. Its too bad north america has gone to central heating and box stoves vs europe side thats mostly masonry heaters, they figured it out, north america is behind slowly learning thanks to the small group and their hard work.

Have you ever tried calculating the efficiency of your build ?
My 4 yr old mass heater ticks over at 40°C surface temperature of flue pipe where it exits the room (about @ the right angle on your design), if I push it hard I can get the flu surface temp upto 70°C (full gasification is achieved within a few minutes of lightning)
You shouldn't need to build a second RMH simply extend your thermal mass connected through a wall via ducting if you can maintain a draft (a computer cooling fan on the air inlet could be an option if you're struggling)

what about indoor air quality, have you measured for pm2.5/10 particles?

how to not carbon monoxide yourself with that thing?

do you burn newspapers, plastics in that thing?

how bad does it smell outside?