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This Simple Heater Could Save Serious Energy

Most folks who want change will tell a dozen people how bad people should stop being bad. Over a 10 year span of time, they may have told 100 people about which bad people to be angry at. Meanwhile, change may or may not have occurred. My approach to change is different. Instead of being angry at bad guys, I'd rather concentrate on bricks to build a better world.

I am a certified master gardener and a permaculture advocate. I founded two online communities: the permaculture site,, and the software engineering site, When I found out that 75 percent of home energy use was for heating and cooling, I went about finding a way to reduce that energy use and learned about rocket mass heaters. Now, I'm releasing a DVD about how to build them safely and effectively.

While 75 percent of home energy use is dedicated to heating and cooling, rocket mass heaters could be the most sustainable way to heat a conventional home and thus reduce our energy consumption. It's the cleanest way to produce heat because the exhaust is often only water and carbon dioxide, instead of the usual plethora of nasty particles and gases coming out of a conventional wood stove. They also require very little fuel. Some people have even reported heating their home with nothing more than the dead branches from their yard.

The cornerstone of this technology is the heat riser, which is where all of the smoke finishes burning up. The heat riser also creates a strong convective current that draws air through the wood feed. This air draft causes the fire to burn sideways and prevents the smoke from coming inside the house. Where most conventional wood stoves use a lot of the heat to push the smoke out of the house, a rocket mass heater accumulates as much heat as possible in the mass before releasing the gases. Therefore, more heat stays in the home for the same amount of wood burnt.

One of the downsides of rocket mass heaters is the fact that they are made of cob and thus are heavy and cannot be built by everybody, especially people renting apartments. So, I tried to come up with a design in which the rocket mass heater could be taken apart and loaded onto a truck in one hour, then put back together in another hour. My first attempt was on Earth Day 2011 in Missoula, Montana. We built the rocket mass heater in an hour and 10 minutes.

Last October, we tried a design featuring a special heat riser core. This allowed us to build the heater in 44 minutes. I took tons of video footage and I just finished running a Kickstarter campaign to put together four DVDs on rocket mass heaters. We got funded, even over-funded, and we were just shy of our stretch goal of 100,000 dollars.

Explaining all of the details of rocket mass heaters in detail in one article would be almost impossible, but I have made gobs of videos, written articles about them and discussed them at, so I invite you to have a look there or join the conversation on Twitter if you want to find out more. Building your own rocket mass heater could save you (and the world) a whole lotta energy.


This project was featured in GOOD's Saturday series Push for Good our guide for crowdfunding creative progress.

Challenge a neighbor to GOOD's energy smackdown. Find a neighbor with a household of roughly the same square footage and see who can trim their power bill the most. Join the conversation at

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