This is a wonderful rocket mass stove by
Estonia. Rocket stoves have very efficient combustion, where the
furnace temperature ranges from about 1000C up to 1100C. This type
of stove, with a cob bench that carries the heat from the stove
through pipes, takes 3-4 people about 3-4 days to build. If you
would like to build a rocket stove we recommend the book, right,
available direct from the author.