I wonder what the efficiency is compared to a modern "rocket stove" build [1] Mass rocket stoves are _incredibly_ efficient. So much so that I've always wonder

I wonder what the efficiency is compared to a modern "rocket stove" build [1] Mass rocket stoves are _incredibly_ efficient. So much so that I've always wondered why more similar designs weren't used in times when the primary heat sources were wood, etc. 1 - https://www.youtube.com/watch?v=fwCz8Ris79g https://www.youtube.com/watch?v=fwCz8Ris79g (skip to 1:50 if you want to see a full one and not the ms paint diagrams)