Free Heat is a 2 hour and 18 minute film that explores the world of rocket mass heaters, a highly efficient and environmentally friendly type of wood-burning technology. The movie follows the experimentation and implementation by a team of experts working on various types of rockety contraptions. Viewers will see firsthand the innovative ways in which the rocket systems are being used and developed, and will learn about the many benefits of this technology. Whether for heating a home, cooking a meal, or creating a relaxing sauna experience, rocket mass heaters are a versatile and sustainable technology. Topics include:

The basics 

The basics of RMH design, build, safety, function, and maintenance. Learn the fundamentals to start your rocket mass heater journey.

A standard, 8 inch, pebble style j-tube

The standard, 8 inch, pebble style j-tube rocket mass heater is a basic, yet incredibly high performing system built inside the solarium at Wheaton Labs.

6 inch cob style j-tube rocket mass heater

A versatile rocket mass heater that you can fit in complicated spaces or small structures like tiny houses made out of cob.

Lorena style rocket cooktop

The rocket cooktop just got an upgrade! The Lorena design allows for the rocket flame to heat the pot directly.

Sauna rocket heater

Select Dynamic field

Uncle Mud's cottage design has been adapted to the sauna at Wheaton Labs. Find out how to make a very efficient rocket heater to sweat it out!

 Solar food dehydrator with a rocket assist

We inserted a rocket system inside a solar food dehydrator to allow dehydration during the night or at times of the year when sunlight is scarce.

The Liberator commercial heater

The Liberator is a commercial rocket heater available in the USA, We tested its capabilities alongside Sky Huddleston, the creator of this contraption.

The Gamera commercial heater

The Gamera is a Bulgarian commercial rocket heater available in Europe, we connected a coaxial heat exchanger to add a mass inside the Red Cabin.

Rocket kiln

We fired some clay and melted some aluminum - a step toward more sustainable ceramics and metal-working.

Juice-box stratification

A scheme to squeeze out a little more efficiency from the already breathtakingly efficient 8-inch system.

Challenges with the 4 inch j tubes

We no longer use 4 inch j-tubes at Wheaton Labs, find out why and the reasons the 6 inch j-tubes are a far better option for us.

Cold Plugs

If we try to start a fire when the temperature outside is warmer than the mass, we will get a cold plug. As the fire starts, the fire is hot. Then we extract nearly all of the heat until the resulting exhaust is about room temperature. The exhaust does not rise. Cold plug.

Meet the instructors!

Paul Wheaton
aka The Duke of Permaculture, is an author, producer, and certified advanced master gardener. He has created hundreds of youtube videos, hundreds of podcasts, multiple DVDs, and written dozens of articles and a book. As the lead mad scientist at Wheaton Labs, he's conducted experiments resulting in rocket stoves and ovens, massive earthworks, solar dehydrators and much more.
Uncle Mud
aka Chris McClellan raises free-range, organic children in the wilds of northeast Ohio. Between building things out of mud and junk he writes for Mother Earth News Magazine and teaches simple DIY skills at workshops and fairs.

Rodney Morgan
has a Masters in Sustainability and has been working with energy building energy efficiency and alternate designs for over 15 years. He is a Small Wind installer, CPHC (PHIUS, Passive House), Landfill Manager, Hazcom 40, and Mud Buddie. In short, an overeducated mechanic that enjoys playing in the mud and preserving the planet.
Sky Huddleston
is an experienced entrepreneur with a demonstrated history of working in the renewable energy industry and commercializing obscure technologies. Over a decade of combustion system engineering experience, including the engineering of diesel engines, aircraft engines, and biomass combustion systems for residential and commercial applications. Extensive experience in mechanical engineering, drafting, and design. He is currently the CEO of Liberator Rocket Heaters, which has the world's first and only rocket mass heater that is tested and certified to being compliant with UL-1482, ULC-S627, ATSM-E-1509 safety standards, and fully EPA certified.
Isaac Workman
became interested in Permaculture in his teenage years. After attending a PDC in 2016 he decided this would be a direction he would pursue for his life. Since 2019 Isaac has been pursuing opportunities and projects that allow for learning and practice in natural building, wood working, farming, and videography. Isaac often spends his other time working on sailboats.
J.R. Megee
is a turkey herding, pig wrangelin permaculture lovin handyman that people are crazy enough to give him money for, Rocket mass heater builder, and certified Garden Master. Was in the first permaculture design coarse at Wheaton Lab also has been through Geoff Lawton's online design course.
Christina Keegan
organizes mutual aid projects with neighbors in Cleveland, Ohio to meet basic needs, advance housing justice, and advocate for greater community control of decision-making. Her work as a grant writer, project manager, teacher and builder focuses on developing healthy, affordable housing and community self-reliance. Her tools include rocket mass heaters, natural building, Permaculture and other urban land regeneration practices.
Kirk Mobert
is a natural builder who has taught with Cob Cottage Co. and around California for over a decade. Kirk's particular interest in Rocket Stoves and Rocket Mass Heaters is in providing a pathway to super efficient, high technology solutions; with low technology, do it yourself methods. Kirk, also known as Donkey, is the administrator of, a hotspot for discussion and innovation of all things Rocket Stove.

Free Heat

6 3D Plans


Detailed, step by step 3D plans for:

  • Pebble style rocket mass heater
  • Solar food dehydrator with rocket boost
  • Rocket cooktop with Lorena option
  • Coaxial heat exchanger
  • Sauna rocket heater
  • Cob style rocket mass heater


Free Heat


Free Heat Movie

More than two hours featuring:

  • The basics
  • A standard, 8 inch, pebble style j-tube
  • A 6 inch cob style j-tube rocket mass heater
  • Lorena style rocket cooktop
  • A sauna rocket heater
  • A solar food dehydrator with a rocket assist
  • The Liberator commercial heater
  • The Gamera commercial heater
  • A rocket kiln
  • A new juice box stratification design
  • Challenges with the 4 inch j-tubes
  • Cold plugs


Free Heat Combo

Movie + 6 3D Plans

  • Free Heat Movie
  • Free Heat 3D plans
  • Rocket Mass Heater Risers eBook
  • Rocket Engine 3D plans
  • Heating Greenhouses with Rocket Mass Heaters webinar



FREE Pebble Style Rocket Mass Heater 3D Plans

Sign Up to our Newsletter at and get a free copy of the 3D plans detailing the Pebble Style Rocket Mass Heater that is approachable for anyone from the novice to the seasoned RMH builder.

COPYRIGHT © 2023 Paul Wheaton