Table Of ContentUS/CAN $39.95 HOME / SUSTAINABLE BUILDING
the rocket mass heater t
h
e
BUILDER’S GUIDE r
o
COMPLETE STEP-BY-STEP CONSTRUCTION, MAINTENANCE AND TROUBLESHOOTING
c
…this book is an essential addition to every homesteader’s and builder’s library. k
— Toby Hemenway, author, Gaia’s Garden and The Permaculture City
e
The second, more comprehensive work on revolutionary wood heating; thorough, technically advanced,
t
comprehensive, well thought-out by the experienced masters of rocket stoves.
— Ianto Evans, director and founder, Cob Cottage Company, inventor of Rocket Mass Heaters and Lorena Stoves m
HEATING WITH WOOD is often considered a natural and economical alternative to electricity or fossil t he
a
fuels. However, even with a fairly new and efficient woodstove, many cords of wood are required for burning
over the course of a single winter, and incomplete combustion can contribute to poor air quality. s rocket
A rocket mass heater is an earthen masonry heating system which provides clean, safe and efficient warmth s
for your home, all while using 70-90% less fuel than a traditional woodstove. These unique and beautiful
installations provide luxurious comfort year-round. In cold weather a few hours of clean, hot burning can h
mass
provide 20 or more hours of steady warmth, while the unit’s large thermal mass acts as a heat sink, cooling
e
your home on sizzling summer days. Packed with hard-to-find information, The Rocket Mass Heater Builder’s
Guide includes: a
• Comprehensive design, construction, and installation instructions combined with t
heater
detailed maintenance and troubleshooting advice e
• Brick-by-brick layouts, diagrams, and architectural plans augmented with detailed
r
parts drawings and photographs for clarity
• Relevant and up-to-date code information and standards to help you navigate the GB
approval process with local building departments. UU BUILDER’S GUIDE
II
DL
Earthen masonry heating systems are well-suited for natural and conventional builders alike. A super-efficient, D
E
wood-burning, rocket mass heater can help you dramatically reduce your energy costs while enhancing the E COMPLETE STEP-BY-STEP CONSTRUCTION,
beauty, value, and comfort of your home. R
MAINTENANCE AND TROUBLESHOOTING
’
S
…represents more than ten years of collaboration and lessons learned from hands-on building and
experimentation. The result is a frank, practical and detailed discussion of design and construction,
pros and cons, and helpful anecdotal stories. While passionate about empowering the owner-builder,
the authors also address code compliance and stress fire safety.
— Catherine Wanek, author, The New Strawbale Home and The Hybrid House, co-author, The Art of Natural Building
Distills the best, most tried-and-true design for efficient, low-cost, low-effort, carbon-neutral, regenerative E
r
home heating. It will be hard to improve upon the wisdom of this book. i
c
a
— Albert Bates, author, The Biochar Solution &
E
r
Erica and Ernie Wisner have built over 700 super-efficient, clean-burning rocket stoves and masonry n
i
heaters. They are dedicated to the search for sustainable solutions and the hands-on teaching of creative, e W
ecological, and practical skills.
i
s
n
e
r
Erica Wisner
www.newsociety.com & Ernie Wisner
Praise for
The Rocket Mass Heater Builder’s Guide
Finally — a comprehensive book about rocket mass heaters! This should put an
end to the freak shows of flaming death showing up on YouTube mislabeled as rocket
mass heaters. And put an end to getting the same questions asked over and over again.
We can start every answer with: “Have you read The Rocket Mass Heater Builder’s Guide?”
— Paul Wheaton, founder of Permies.com online community
Eagerly awaited by homesteaders both urban and rural, appropriate tech folks,
and do-it-yourselfers of all stripes, The Rocket Mass Heater Builder’s Guide is a
comprehensive, well-researched, and clearly illustrated manual on one of the most
exciting home-heating concepts to come along in decades. The book is firmly
grounded in the authors’ many years of experience, will save every builder vast
amounts of toil and frustration, and paves the way to a home-heating system that
is clean burning, marvelously fuel efficient, and a pleasure to live with.
Rich in detail without being overwhelming, this book is an essential
addition to every homesteader’s and builder’s library.
— Toby Hemenway, author, Gaia’s Garden and The Permaculture City
An advanced companion to Rocket Mass Heaters: Superefficient Wood Stoves
You can Build and Snuggle Up To. The second, more comprehensive work on
revolutionary wood heating; thorough, technically advanced, comprehensive,
well thought-out by the experienced masters of rocket stoves.
— Ianto Evans, director and founder, Cob Cottage Company,
inventor of Rocket Mass Heaters and Lorena Stoves
Drawing on the centuries-old tradition of masonry stoves and heaters,
the “rocket” mass heater offers a modern, fuel-efficient way to heat a home with wood.
This Guide represents more than ten years of collaboration and lessons learned from
hands-on building and experimentation. The result is a frank, practical and detailed
discussion of design and construction, pros and cons, and helpful anecdotal stories.
While passionate about empowering the owner-builder, the authors
also address code compliance and stress fire safety.
— Catherine Wanek, author/photographer, The New Strawbale Home and The Hybrid House,
and co-author, The Art of Natural Building
In The Rocket Mass Heater Guide, Erica and Ernie Wisner have
distilled the best, most tried-and-true design for efficient, low-cost, low-effort,
carbon-neutral, regenerative home heating. Undoubtedly people will continue
to experiment, but it will be hard to improve upon the wisdom of
this book — what works, what doesn’t and why.
— Albert Bates, author, The Biochar Solution
You will be happy to own this book for years and years to come!
There are life-changing secrets inside of Erica and Ernie Wisner’s most remarkable
book, ways of understanding how to live better, more simply, and more beautifully
while also being more snuggly and cozy that you ever thought possible!
— Mark Lakeman, co-founder, City Repair and design director, communitecture
Over the years, a handful of dedicated practitioners and authors have helped
the natural building movement advance their craft based on solid engineering
and experimentation. The authors are among that elite and vital group, and
this book is a must-read for anyone who longs for practical, detailed
knowledge on rocket mass stoves based on extensive experience.
— Dan Chiras, Ph.D., director, The Evergreen Institute and author,
The Natural House and The Homeowner’s Guide to Renewable Energy
Biomass energy is sensible when used super-efficiently and locally — which
is the point of this book. Folks who live in cooler climates can benefit
enormously from this simple, do-it-yourself technology.
— Richard Heinberg, Senior Fellow, Post Carbon Institute
The Rocket Mass Heater Builder’s Guide provides a remarkable amount of detail for
designing, building and using these elegant and efficient space heaters. In a world of
ever-diminishing resources, growing populations and changing climates, safe, efficient
and low-cost solutions to space-heating without fossil fuels are vitally needed. I have long
planned to build a high mass rocket stove in my bioshelter/ greenhouse to replace our
woodstove. After reading this book, I feel inspired and feel confident to do it.
— Darrell E. Frey, author, Bioshelter Market Garden: A Permaculture Farm
Copyright © 2016 by Erica Wisner and Ernie Wisner.
All rights reserved.
Cover design by Diane McIntosh.
All photos and diagrams are by the authors unless otherwise noted. (See also image captions.) Cover diagrams,
top and bottom row: by author. Center left: Greenhouse heater firebox, photo by owner; see color in-
sert. Center right: Mediterranean heater with ceramic bangles, photo by Adi Segal — see Chapter 3.
Interior: Flames © AdobeStock_60101445; White brick © AdobeStock_69829337; Smoke background ©
AdobeStock_72849210; Adobe mud © AdobeStock_49425959
Printed in Canada. First printing April 2016.
This book is intended to be educational and informative. It is not intended to serve as a guide. The author and
publisher disclaim all responsibility for any liability, loss or risk that may be associated with the application of
any of the contents of this book.
Paperback ISBN: 0-978-86571-823-4
eISBN: 978-1-55092-616-3
Inquiries regarding requests to reprint all or part of The Rocket Mass Heater Builder’s Guide should be addressed
to New Society Publishers at the address below. To order directly from the publishers, please call toll-free (North
America) 1-800-567-6772, or order online at www.newsociety.com
Any other inquiries can be directed by mail to:
New Society Publishers
P.O. Box 189, Gabriola Island, BC V0R 1X0, Canada
(250) 247-9737
New Society Publishers’ mission is to publish books that contribute in fundamental ways to building an ecolog-
ically sustainable and just society, and to do so with the least possible impact on the environment, in a manner
that models this vision. We are committed to doing this not just through education, but through action. The
interior pages of our bound books are printed on Forest Stewardship Council®-registered acid-free paper that
is 100% post-consumer recycled (100% old growth forest-free), processed chlorine-free, and printed with
vegetable-based, low-VOC inks, with covers produced using FSC®-registered stock. New Society also works to
reduce its carbon footprint, and purchases carbon offsets based on an annual audit to ensure a carbon neutral
footprint. For further information, or to browse our full list of books and purchase securely, visit our website at:
www.newsociety.com
Library and Archives Canada Cataloguing in Publication
Wisner, Erica, 1977-, author
The rocket mass heater builder’s guide : complete step-by-step construction, maintenance and trouble-
shooting / Erica Wisner & Ernie Wisner.
Includes index.
Issued in print and electronic formats.
ISBN 978-0-86571-823-4 (paperback).--ISBN 978-1-55092-616-3 (ebook)
1. Rocket mass heaters. 2. Rocket mass heaters--Design and construction. 3. Rocket mass heaters--
Maintenance and repair. I. Wisner, Ernie, 1968-, author II. Title.
TH7438.W58 2016 697’.1 C2016-900792-8
C2016-900793-6
Contents
Acknowledgments and Background .............................................. vii
Chapter 1: Rocket Mass Heater Overview
and Terms .............................................. 1
Chapter 2: General Design Considerations .............................................. 25
Chapter 3: Design Examples .............................................. 39
Chapter 4: Step-by-Step Construction Example .............................................. 59
Chapter 5: Operation and Maintenance .............................................. 101
Chapter 6: Rules and Codes .............................................. 137
FAQs .............................................. 163
Appendix 1: Earthen Building .............................................. 179
Appendix 2: Rocket Mass Heater Building Code
(Portland, Oregon) .............................................. 199
Appendix 3: Special Cases .............................................. 205
Appendix 4: Home Heating Design Considerations .............................................. 225
Appendix 5: Wood Heat Considerations .............................................. 241
Appendix 6: Supplemental Practice Activities .............................................. 257
Index .............................................. 269
About the Authors .............................................. 277
v
Acknowledgments and Background
Heating and cooling represents 30% clean-burning heat, using locally available
to 60% of most household energy and nontoxic materials; and we continue to
budgets. Rocket mass heaters offer a sub- encourage owners to integrate these heaters
stantial savings on both heating and cooling into smart, efficient, compact, passive solar
in many climates. We hope that this book cottage designs.
will prove useful as a small but practical Ernie Wisner joined this field as part of
step in addressing many key problems of our a dirty-hands research team under Ianto’s
time: uncertain economies, deforestation and banner at the Cob Cottage Company.
small fuels accumulation in our New World Working in the US Navy, commercial fish-
landscapes, the need for alternative energy eries, geophysical exploration, fire-fighting,
and for more energy-efficient ways of meet- and hazardous materials disposal, he saw and
ing everyday needs, preserving clean air and did some of the dirty jobs required by many
water, and ultimately, making life on Earth common industries. He started looking for a
more comfortable and pleasant for both hu- field of work that wasn’t self-defeating: some-
manity and the vast web of all life. Even if thing sustainable. Cob Cottage Company
we can’t know all that, we hope this book offered a dirt-cheap way to build perma-
will at least give the reader hope for a more nent, healthy, and attractive dwellings, and
comfortable, safer, more affordable, and less a chance to practice appropriate/improvised
toilsome future. technology for emergency preparedness and
Rocket mass heaters would not exist disaster relief.
without the pioneering work of Ianto Evans, During intensive research session in 2004–
documented in the Evans/Jackson book 2006, Ianto, Ernie, and others built hundreds
Rocket Mass Heaters, now in its third edi- of test systems in an effort to diagnose re-
tion. On those foundations we continue ported problems. That work contributed to
to develop ecologically-sound, efficient, the first Evans/Jackson book collaboration,
vii
viii The Rocket Mass Heater Builder’s Guide
and to an ongoing grassroots development have learned a great deal from troubleshoot-
community including online forums hosted ing other builders’ work as well as our own.
at proboards.com and permies.com. We are grateful to the friends, family, and
Ernie wanted to document all the ex- colleagues who have supported us through
perimental data for inclusion in the Evans/ the many years’ process of developing and
Jackson book, but the team felt that too much documenting this information.
technical information would overwhelm the We would not have been able to do this
average reader. They acknowledged the value without the support of friends, family, and
of a technical manual, however, perhaps as collaborators — particularly those who
a separate publication. Erica joined the ef- helped with contributions and work opportu-
forts in 2006/7, with experience in writing, nities during the time immediately following
instructional illustration, and hands-on Ernie’s 2006 injury, and who helped make
teaching. For the past ten years Ernie and our work known through YouTube, per-
Erica have been teaching workshops togeth- mies.com, rocketstoves.com, richsoil.com,
er, helping owner-builders to learn and build and magazines such as Home Power maga-
prototypes, and refining the design of these zine, Mother Earth News, and Permaculture
heaters for reliable performance in conven- magazine.
tional buildings. Some colleagues and contributors are
This book, then, is a hybrid of Erica’s noted with their projects in Chapter 3 and
desire to present information in a step-by- Appendix 3, but many others have offered
step instructional manner, and Ernie’s desire encouragement and insightful questions.
to share in-depth technical information. Paul Wheaton and Kirk Mobert deserve our
It offers more specifics and depth than the thanks as custodians of the permies.com and
Evans/Jackson book, helping the reader proboards.com forums.
avoid known problems, and clarifying our Some noteworthy contributions to the
favorite methods for the trickier parts of field of clean heat include David Lyle’s
construction, operation, and maintenance. The Book of Masonry Stoves; Jim Buckley
It is a privilege to be alive at this time of Buckley Rumford Fireplaces and www.
when grassroots creative design collabora- rumford.com, and Eric Moshier of Solid
tions can be undertaken with partners around Rock Masonry, amazing masons who have
the world. Builders on all seven continents been gracious enough to correspond about
have contributed examples, questions, prob- foundation work and chimney codes. The
lems, and discoveries to the general store of curators of the online Sweep’s Library have ex-
knowledge in this space. While we admit to panded their shop website with a tremendous
some frustration when new builders repli- amount of down-to-earth public informa-
cate past problems instead of building on tion at www.chimneysweeponline.com, and
past success, the sheer quantity of examples a similar public service is provided by the good
available online helps prove out certain the- folks at woodheat.org, engineeringtoolbox.
ories and rules of thumb much faster than com, builditsolar.com, and the HUD Heating
could be done by any one team alone. We Degree Days Index.
Acknowledgments and Background ix
Thank you in general to those who’ve sup- projects became unfortunate examples of
ported and documented the development of what not to do, largely demolished now.
these heaters: Cob Cottage Company (www. We hope that the chimney-related failures
cobcottage.com); Paul Wheaton (www.rich in particular may be more easily understood
soil.com) and the Permies.com forums com- and remedied with the information in these
munity; Calen Kennett (www.villagevideo. pages.
org); Bart Glumineau (www.studiomelies. Colleagues who helped develop the
com); Olivier Asselin (www.possiblemedia. Portland, OR, rocket mass heater code (Ap-
org); Adi Segal (www.adisegal.com); Priscilla pen dix 2) include Joshua Klyber, Bernhard
Smith; Arthur Held; Bryce Phelps; Eric Masterson, and the City of Portland’s Al ter -
Moshier (www.solidrockmasonry.com); Lasse na tive Technologies Advisory Committee.
Holmes; Max Edleson (www.FireSpeaking. For useful editorial and proofreading
com); Flemming Abrahamsson (www.fornyet comments, we wish to thank Stephen, Anna,
energi.dk); Peter van den Berg and Kirk Rebecca, Catharine, Leslie, Lindsay, Rob,
Mobert (donkey32.proboards.com); Leslie and all those who field-tested draft versions
Jackson (www.rocketstoves.com); and all of this book. Thank you Linda, Rob, Sue,
the others who’ve helped to make this infor- Greg, Maddy, and the whole publishing team
mation available and accessible. from New Society and our overseas partners.
Thank you to all the owners, builders, For personal support and generosity, and
workshop participants, and correspondents raising us along the way, we acknowledge
whose projects served as learning opportuni- and thank all of our families, friends, and
ties and proofs of concept. Most have opted collaborators. Any list would never be com-
for privacy over public acclaim, but we are plete. So:
especially appreciative of those who agreed
to share their project details in Chapter 3. Thank You.
We also wish to thank (and apologize to)
those early clients and collaborators whose
