I have lived almost my entire life in homes that have been heated with wood in one way or another. From a giant wood furnace in the basement of an old Ontario farmhouse to an elegant little pellet stove in a city home in Peterborough, I have enjoyed the process of burning wood to keep warm.
Rocket stove revolution
With this kind of background, it’s no wonder that I have followed closely the development of “rocket stoves” over the past decade. From their beginnings as a means to provide efficient cooking heat from minimal fuel in developing countries, the promise of rocket stoves has been intriguing for any wood burning enthusiast. However, the open “J-tube” style of most rocket stoves meant that the feed tube for the fire was open inside the home with all the attendant dangers. In addition, the wood used in J-tube stoves is small dimension, which is perfect for cooking where fuel is scarce but as a home heating device means constant attention and stoking is required. For these reasons, I have been hesitant to recommend rocket stoves as a home heating system, except for the strong-hearted devotees of the idea.
Rocket mass heaters – suitable for indoors!
However, the development of “rocket mass heaters” brings the rocket stove idea to the point where it is a feasible home heating device. This style of rocket stove blends the safety and efficiency of the masonry heater with the do-it-yourself approach of the rocket stove. I was privileged to be able to take a workshop on building rocket mass heaters with Andrew Brunning of Rocket Mass Heaters.
The design of the rocket mass heater, or batch box rocket stove, was developed by Peter van den Berg, and its genesis is explained in this article in Permies. The heater combines the simple construction and burn characteristics of a rocket stove with a full masonry burn box, as with a masonry heater or typical wood stove, which can have a closed door with or without glazing. One fill of the burn box equals several hours of burn time and many more hours of heat from the mass built around the stove.
How to build a rocket mass heater
The workshop with Andrew allowed the participants to help build the rocket mass heater, as well as the large mass bench that would be the recipient of the heat generated. The photo gallery below gives a good overview of the process:
Rocket mass heater workshop coming to Endeavour in 2015
I look forward to building one of these rocket mass heaters for myself. And Endeavour looks forward to bringing Andrew to the school in 2015 for a hands-on workshop!