Building a Rocket Mass Heater – Using a New Trick

Helping to heat green houses everywhere, one rocket mass heater at a time…This project was certainly an example in collaboration, as we worked with Groundswell Community Green House in Invermere BC to the host the event, and built the actual heater in a green house out at Edible Acres farm in Windermere, BC. If it was an excellent effort in collaboration, it was also a great, and humbling, example of our continued influence, as many of the students traveled from far and wide to attend.

Rockets are always different, and depend on the available material, the space, and the size of the system. This is what makes them so adaptable, and affordable to build. One element that we are particularly happy with in this build is the use of a half barrel for the manifold. (See this project for an example of a manifold constructed out of brick). This is the that basically connects the heat riser to the stove pipe that runs through the bench. We love this new adaptation: supper affordable, unbelievably easy to use (this component only took about 1/2 hr, comparatively, when constructed out of brick, it always seems to take hours!). And all you need is a jigsaw. We actually can’t believe how simple and effective it was. This is definitely a modification that we would recommend.

Here are some photos (and a short video of the first firing!)

Testing our mock up.

Building the combustion unit.

Rocket mass heater manifold with barrel for manifold







Putting together the half barrel manifold. The barrel was measure to the right height, and cut to fit around the combustion unit, as well as to fit the stove pipe (on the opposite side, not pictured). We used wood stove door gasket and glue to attach the two barrels together. Later, that joint was sealed again with cob.

The guts of the rocket, including combustion unit, barrel manifold and steel pipe heat riser.


 Just before we tested the unit.


 Enjoying a salmon feast from the cob oven on Saturday night. It was great to be eating out of this oven exactly a year after the workshop was held! Thanks again to Bill and Ally for the food.









 rocket mass heater cobbing in_0

Cobbing in the whole unit.


Great group, with students from far and wide! Thank you everyone.

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