“Rocket Mass Heaters” is a great idea for heating your home IF you are interested in wood heat. It may not work for most homes that are in neighborhood additions or the city, however, the concept is great. Normal wood stoves contain several logs in an air-tight cast iron stove, with a stove pipe rising up to the ceiling and out the roof or curved out the back wall and then rising up above the roof line to prevent spark-ignition on buildings and roofing materials. The Rocket Mass Heater is a sealed unit that has an internal heat riser, which then requires the heated gases to sink down around a large “barrel” object (like a paint-free 55 gallon barrel) and down into 16 to 24 feet of 6 to 8 inch tubing in the heat sink (or bench area). The heat from the gases dissipates into the heat sink and ejects outside of the building as Carbon Dioxide and water.
It is the most efficient wood stove burning concept and provides a great seat-warmer, which will then dissipate heat over the next 24 to 48 hours into the room. In conventional open hearths, outside of some radiant heat from the open fire, most of the heat is sucked right up the chimney. In wood burning stoves, heat radiates from the metal and stove pipe into the room, but most heat still goes up the chimney. There are other better designs, but nothing like the Rocket Mass Heater. The design almost makes a redneck (like me) want to move to a new house where one could be built and enjoyed during these long winter months we’ve experienced.
Evans has provided excellent explanations, dimensions, drawings and a wood burning philosophy. It’s simple to read and easy to understand. He’s revealed many of the lessons he has learned through his own mistakes, which explain his recommended drawings. He describes the materials and tools you’ll need as well as recommended dementia and proportions. He also answers many questions in trouble-shooting as well as drawbacks of Rocket Stoves. Interestingly, I didn’t hear of someone keeping their home at 72 degrees; normally it seemed I read 55-60 degrees were stated, but with a warm bench to sit on, he said, that was all most people wanted! (I guess I’d want a back up for those rooms that might not have a clear shot at the radiant heat!)
It might not work for most city-folk, but for those who have an easy supply of wood, it sounds like a efficient heat design and requires far less wood than most other wood burning stoves!