Max,
As a builder of rocket style mass heaters the firebox design work has thus far been completed by Peter van den Berg for me. How do you go about designing a firebox in a “traditional” masonry heater?
I’ve looked at various literature from the MHA including their published stove designs and aside from references to the Austrian heater calculator I haven’t found anything specific about the process. I’m aware of the kilowatt per hour calculations to arrive at a kilogram per hour firebox sizing but how does that translate to the other variables such as flue size and air intake?
While we are on the subject what is your current firebox style, meaning floor grates or no secondary air through wall channels etc?
thanks for sharing your knowledge!
Anyone looking for a more traditional (non rocket) firebox check out Alex Chernov’s free cook stove plans available by request. You can reach him through his website at stovemaster.com. I used this firebox in a rebuild of a rocket style stove this year and couldn’t be happier.
Would you mind elaborating on the differences between the more traditional masonry heater vs a rocket style masonry heater? I know about rocket stoves and their riser (or riserless, like Matt’s stove designes) cores and I know about the baffled systems of traditional masonry heaters, but I’m confused about the difference between the fireboxes. Don’t They both burn wood at VERY high temps so as to pyrolyze and burn up nearly 100% of the gasses of the wood in addition to the wood itself? Why would I choose one design over the other?
I will do my best but will certainly make some mistakes.
The various rocket stove designs all have a burn chamber attached to a secondary burn chamber through a port to encourage mixing and more complete combustion. Some have a vertical secondary chamber others horizontal but all are made with an insulating form of refractories to encourage combustion.
The traditional firebox takes the approach of attempting all combustion in the firebox although I’ve read of some designs with bread ovens that use that as a secondary burn chamber.
Generally I would say and this is certainly not true in all cases that a traditional firebox burns a little dirtier but is cheaper and easier to construct. They are larger in volume and start easier with less obstruction. Having constructed examples of both as a builder and end user I prefer the one traditional style to all the various rocket stove interactions(by this I mean I’ve constructed a single stove using a traditional box and several stoves using p-channel, dsr 1,2 and 3 as well as j tube designs). A large factor as a builder is end users have a difficult time following instructions. So a design that is more forgiving is always better for me and the client.
You can read more on these subjects with in depth analysis at
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It is definitely worth noting there are a myriad of firebox designs that I have lumped together as “traditional” but several of them are quite new.