Rocket Stoves (rocket mass heaters) are heaters; they heat the house. They’re “super efficient furnaces.”
FURNACES INFORMATION: The efficiency of furnaces is measured in AFUE, which is a number that shows the percentage in efficiency (A greater AFUE results in a greater efficiency). High efficiency furnaces range from 90 to 97%, while low efficiency furnaces range from 80% and less.
90-97% is already pretty efficient for a furnace, so how can rocket stoves beat that? I don’t even know. The efficiency of rocket stoves haven’t been professionally analyzed yet, so there’s not really a specific number that shows it; not in the AFUE (if someone can tell me otherwise, please do! I’ve been looking for an answer from many sites now, but I can’t seem to find a proper answer). Guaranteed however, rocket stoves are a very efficient way to heat up one’s house (efficient as in the amount of fuel – wood – put in will bring you a lot of heat, and for a long time too – which is up to 4 days).
In the picture on the right: Wood and oxygen go in on one side to be burned in the burn chamber and then transferred into the steel drum. The steel drum brings out some of the heat directly out into the house for immediate heating, while the rest of the heat is transferred through a long, airtight duct to keep the heat circulating around the house to have constant heating. The duct is usually covered with clay, mud, stone and many other materials and then covered with a ceramic spray to keep everything together. This clump of clay, mud and stone (and many more materials) that covers the duct can be used a furniture; a couch; a bed; a table; anything.
This is the only website I’ve seen so far that sells rocket mass heaters: