Free Heat

Free heat is possible with a rocket mass heater. Some call it "carbon neutral," others "carbon negative." Heat your home with yard waste and cardboard while reducing global problems.



Rocket mass heaters

are possibly the most powerful solutions to many of the problems confronting individuals and the global population today. For individuals, Rocket Mass Heaters can save thousands of dollars and bring greater comfort. For some, this could even mean free heat. Around our world, if a billion people used Rocket Mass Heaters as their primary source of heat, it would solve a list of global issues. The only barrier to this solution is . . . knowledge.



A rocket mass heater is:

  • cheap to run. About a tenth the cost of natural gas, electric or conventional wood heat.
  • clean. They emit about a hundredth of the smoke of a conventional wood stove.
  • good for the environment. Less than 2% of CO2 emissions of natural gas or electric heat. Can reduce your carbon footprint as much as parking 7 cars.
  • sustainable. It uses a renewable fuel which is easy to find and store.
  • cheap to build. About $200 to $600.
  • quick to build. Often built in a weekend
  • luxuriant. Like the luxury of a heated floor but without all that standing.


Rocket Mass Heater advantages:

  • In comparison to a conventional wood stove, they:
  • let off heat gradually over the day, so you don't need to keep tending it.
  • They burn up the creosote, making the burn not only safer, but also more efficient.
  • They generally require about 1/10 of the wood to heat your home.
  • By using junk mail and sticks from your yard, free heat is possible.
  • Even if you purchase the firewood, it still costs less to operate than natural gas

What the experts say:


Rocket mass heaters cut the heating bill by 98%. A wood burning contraption you can build. Compared with a conventional wood stove, it heats with one tenth the wood and one thousandth the smoke. Switching to rocket mass heaters from electric heat in a cold climate cuts 29 tons of carbon.


Chris "Uncle Mud" McClellan

The winter of 2013-14 was particularly harsh where I live in Cleveland, Ohio, but we managed to keep warm AND keep our fuel bill around $100 for the whole winter, mostly thanks to these amazing Rocket Mass Heaters we built out of cob and scrap metal.


Ernie & Erica Wisner

The thermal mass is also compatible with passive-solar design (which I consider the ultimate in efficiency, as it's literally zero fuel usage). Thermal mass soaks up ambient warmth from the sun, cooking, kids and pets, or whatever is around, including excess heat during hot summer days.

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

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 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