getting started with rocket mass heaters/ stove

Hi all
just getting started with thinking how a RMH might work in my design so apologies if questions are very basic
1) what is the difference between a rocket mass heater and rocket mass stove
2) Can you design a RMH so it cooks food as well as heating?
3) can you design one that heats water ( I read it can be dangerous as a pressurised system), if so, is it a case of finding alternate way to heat water?
4) The area I am heating is relatively small and well insulated (35 sq metres)- would a small modern stove work nearly as well? ( as easy to purchase off the shelf with a water heater)
5) Also, in a separate refurb in an urban area are RMH recommended (or are there planning issues? has anyone retrofitted a rmh into an old semi-detached house? ( there is no fire place). Does the final exhaust have to always go through the roof or can it go via outside wall?
Apologies for all the questions - all tips gratefully received
John and Grainne

Hi Grainne; Welcome to the wonderful world of Rocket heaters!

1) This is easy , a rocket mass heater is a rocket stove heating a mass. A Rocket mass stove is the same thing.
However a Rocket stove itself is just the core burner assembly without any mass.
2)Yes, easily as a stove top.
3)Yes, as a stand alone water heater it can be easily done. Trying to combine it with a home heating setup would be an issue.
4)A small brick bell batch box might be more to your liking but in some applications a well built box stove can be the right choice.
5)This is a slightly harder one. Yes it has been done. Usually not in city limits (at least not legally) Thru the roof is always better , but yes you can go out the wall and up. BUT you must use expensive insulated chimney pipe.

Ask away Grainne, we have lots of cheerful rocket scientists eagerly awaiting your questions!

EDIT)  Here is a link to a master builder.  Matt sells plans for some outstanding heaters.  You might be very interested in his tiny house cook stove and his new water heater!
http://walkerstoves.com/

Hello Grainne!

We started our RMH journey early last fall, not knowing much of anything and the folks here helped us out more than I can say. Still learning everyday, but I will say we have a much better understanding of rocket mass technology and we now have a working stove.

Thomas and the crew will be able to give you much more advice on the technical side of things than I can for sure. My only advice to you would be, when in doubt, ask questions and really learn about materials and what there uses and limitations are.

Most importantly, insulate insulate insulate! When I say that I’m referring to refractory insulation. You need to focus on making sure the heat goes in the direction that you want and not out the floors or walls etc.

Building your own RMH is an adventure and a challenge, but the knowledge you gain from the experience and the time you spend with your heater is worth every penny and minute spent. Totally customizable to your needs and more than anything you could ever buy off the shelf at the store.

Like Thomas said, Matt from Walker Stoves has some amazing designs that would surely fit your needs and he is extremely helpful with answering questions and guiding you throughout the build process.

If you choose to go the RMH route I wish you all the best. Will keep following.

Cheers, Peter of Hokkaido ⛰🧱⛰

thanks Peter and Thomas, plenty for me to think about and research