Burn a small wood fire.
Air draws the flame through an insulated combustion core. The hot conditions help burn the fuel and combustible gases more thoroughly.
WOOD HEAT, REIMAGINED
Small fire.
Big comfort.
A rocket mass heater pairs a hot-burning wood fire with a bench that stores warmth. Learn how it works, see real builds, and explore the plans to make it your own.
2 movies · 7 plan sets · a risers eBook · a greenhouse webinar
is part of the heater.
A hotter burnA focused fire in an insulated core
Warmth that staysHeat stored in a substantial mass
A place to settle inA bench that gives warmth back
01 / THE IDEA
What if your fire could
keep you warm longer?
Buying fuel. Carrying wood. Starting another fire. Winter heat can ask a lot of you. A rocket mass heater changes the approach: burn the wood well, then store useful warmth for later.
a rechargeable heat battery.
Put the warmth to work.
The barrel releases heat into the room. Hot exhaust then travels through passages in a heavy bench, transferring more warmth before leaving through a chimney.
Enjoy the heat you stored.
Stone, cob, or other thermal mass slowly gives that warmth back. The fire can finish while the bench continues to warm the space.
The difference is the stored heat. A rocket stove makes a hot fire. A rocket mass heater adds a substantial heat store. That is what makes the warm bench more than a seat.
Read Paul’s explanation02 / SEE IT IN ACTION
Meet the people.
See the possibilities.
The Free Heat movie takes you into real builds and experiments, from heated benches to cooktops and saunas. See what works, what needs attention, and how the pieces fit together.
WATCH THE TRAILER FREE HEAT COMBO / MOVIE + 6 3D PLANS
WATCH THE BUILDS. UNDERSTAND THE DETAILS.
CHOOSE YOUR NEXT PROJECT.
RECOMMENDED / THE WHOLE COLLECTIONGo from curious
Go from curious
to ready to plan.
The movie brings the idea to life. The drawings let you study the details. The complete combo puts both in your hands, with more projects and deeper explanations to keep learning.
- Free Heat Movie2h 18m
- Free Heat 3D plans6 plan sets
- Rocket Mass Heater Risers eBook22-page PDF
- Rocket Engine 3D plansAdditional plans
- Heating Greenhouses with Rocket Mass Heaters webinarWebinar
- Freaky Cheap Heat movieSecond movie
$35$189.43
Get the complete combo One purchase. Digital access through Permies.
03 / FROM IDEA TO DETAILS
Six sets of plans.
More ways to use the fire.
Study the shapes, materials, and assembly with step-by-step 3D drawings. The Free Heat plans collection covers two mass-heater styles and four more ways to put rocket heat to work.
before choosing your build.
Pebble-style mass heater
An 8-inch J-tube heater with a bench filled with thermal mass.
Cob-style mass heater
An earthen heater-and-bench design for a small space.
Rocket cooktop
A cooking design with a Lorena-style option.
Solar food dehydrator
A solar drying system with a rocket-heat boost.
Sauna rocket heater
A rocket-powered design for a sauna project.
Coaxial heat exchanger
Explore the heat-exchanger design in illustrated steps.
04 / CHOOSE YOUR STARTING POINT
A little inspiration.
Or the whole collection.
Start with the film, focus on the drawings, or bring the complete collection together in one purchase.
WATCH & UNDERSTAND
The movie
For seeing the heaters, meeting the builders, and getting the big picture.
- Free Heat full-length movie
- 2 hours 18 minutes
- Real builds and experiments
$10$25
Get the movie STUDY THE DESIGNS
The six-plan collection
For exploring the construction details of the six Free Heat projects.
- All six Free Heat plan sets
- 159 pages of illustrated plans
- Step-by-step 3D drawings
$25$104.94
Get the plans WATCH, STUDY & EXPLORE
Free Heat Combo
Movie + 6 3D Plans, with these additional resources included.
- Free Heat Movie
- Free Heat 3D plans
- Rocket Mass Heater Risers eBook
- Rocket Engine 3D plans
- Heating Greenhouses with Rocket Mass Heaters webinar
- Freaky Cheap Heat movie
$35$189.43
Get the complete combo A FEW GOOD QUESTIONS
Before you
light the fire.
A clearer picture makes
the next step easier.
Does “Free Heat” really mean zero cost?
If you have suitable dry wood available locally, you may be able to avoid buying fuel. A heater still takes materials, a suitable installation, time, and maintenance. What you spend and how much heat you get depend on your home, climate, design, and fuel.
What is the difference between a rocket stove and a rocket mass heater?
A rocket stove concentrates on making useful heat from a hot-burning fire. A rocket mass heater also routes heat into a substantial mass, such as a stone-filled or cob bench, so it can release warmth after the burn.
Is the movie enough to start building?
The movie helps you understand the systems and explore different approaches. The illustrated plans let you study specific designs in more detail. Choose a design suited to your space and get experienced guidance on the installation before building.
Will a rocket mass heater work in my home?
It depends on the space, the heating load, and the design. The weight of the mass, chimney, clearances, and local acceptance all matter. Have a qualified local professional review your proposed installation. The resources help you investigate your options before committing to a build.
What exactly am I buying?
These are digital learning resources. The movie offer is Free Heat; the plans offer is the six-design collection. The complete combo also includes Rocket Engine plans, the risers eBook, the greenhouse webinar, and Freaky Cheap Heat. It does not include a physical heater or materials.
How do I get access?
Your purchase and access are handled on Permies. Use the same account and email at checkout that you want to use to return to your resources. The purchase page confirms the current offer and available payment options.
MAKE YOUR NEXT WINTER A DIFFERENT STORY
Bring the idea home.
Start with the know-how.
See the systems. Study the plans.
Find the project that fits your life.