Rocket Mass Heaters

Rocket Mass Heaters are super-efficient wood burning stoves. They incorporate a simple J-tube rocket stove (more to follow), a metal drum to direct the flue gases down and into a system of ductwork, and finally a great deal of thermal mass (usually a cob bench) to soak up all the heat.

Rocket mass heaters are one tool on the path to sustainable independence. Take a moment to consider this image: Imagine a chilly winter day, when the sun is low, and the skies are grey. You have built a small out building that you use as you office, writing studio, or perhaps you have a greenhouse. Instead of having a space heater that is powered by electricity (in the province of Alberta, supplied by a coal fired power plant, most likely) that relies on grid infrastructure, you take your hatchet, split some kindling, and get a roaring fire going. The wood you are using is probably either clean scrap wood from the nearby lumber yard, or perhaps coppiced branches from your caragana bushes.
If you are in your office, you sip your morning coffee, and take a minute to appreciate what you built with your own two hands. You sit down to work, with the fire crackling in the background, releasing radiant heat. If you are in your greenhouse, you stand back, arms folded, satisfied that your plants are warm and happy, and steadily growing to feed you and your family. You are content because through the use of simple technology, you have created a small pocket of resiliency in your life. If need be, you can heat yourself efficiently. This is independence.

In a nutshell, a rocket mass heater can:

• heat a home using a fraction of the firewood
• burn the wood so efficiently that there is virtually no smoke, simply steam and CO2 (after all, smoke is simply unburned fuel)
• maintain heat in a building for several days after only one firing
• be built for under $100 and in just a couple of days
• provide the most beautiful radiant heat!

Why Radiant Heat is Best

The authors of A Pattern Language (Alexander et al. 1977) explain:

People are most comfortable when they receive radiant heat at a slightly higher temperature than the temperature of the air around them. The two most primitive examples of this situation are: (1) Outdoors, on a spring day when the air is not too hot but the sun is shining. (2) Around an open fire, on a cool evening. Most people will recognize intuitively that these are two unusually comfortable situations. And in view of the fact that we evolved as organisms in the open air, with plenty of sun, it is not surprising that this condition happens to be so comfortable for us. It is built into our systems, biologically.

Unfortunately, it happens that many of the most widely used heating systems ignore this basic fact. 

Adaptations of the Rocket Mass Heater 

Rocket Mass Heaters are not reserved for home heating but can be adapted to extend the growing season in a greenhouse. To see how this works click here.

Want More Information?

Read our blog entry on Rocket Mass Heaters titled: Building Rockets in Oregon. Also click here for some of our RMH projects.

Recommended Reading:

Rocket Mass Heaters – superefficient woodstoves you can build (and snuggle up to) by Ianto Evans and Leslie Jackson - www.cobcottage.com (available for purchase through Dirt Craft)