Learning to Build A Rocket Mass Stove

Last Sunday, February 9, a couple dozen people gathered in a cold barn outside Erie, Colorado, to continue work on a rocket mass stove. Learning to build a rocket mass stove is easy, but there are techniques that are helpful.

Here’s a good explanation of the concept:

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If you still don’t get it, here’s the gist: you build a small, hot-burning fire with small pieces of wood. The design of the rocket-mass stove encourages a strong draft, which gets the wood burning vigorously. The hot gases from combustion are drawn through the slightly pitched “chimney,” which transfers its heat to the surrounding cob bench. Cob is a simple earth mixture of clay and sand that is ideal for thermal mass for a cob bench. Building with cob is cheap, simple, and highly labor intensive.

Mike and Avery, who led the workshop, are permaculturalists and natural builders. A few weeks ago, they led a workshop to build the “firebox” and “flue” parts of the heater. Those tasks are more complex, but definitely manageable. They based the design on the book “Rocket Mass Heaters: Superefficient Woodstoves You Can Build” by Ianto Evans and Leslie Jackson.

people stomping cob, then learning to build a rocket mass stove

Stomping cob is energy intensive, so gather as many people as you can.




firebox of rocket mass heater

Here’s where you build a fire in a rocket mass heater.


placing cob on the heat tubes

This is about 35′ of heat tubes, so the heat from the gases can migrate into the cooler cob.

Building with cob is hard work, but very low cost, nontoxic, and flexible with design.

The Farmhouse Media is all about living sustainably through

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