What is a Rocket Mass Stove?


The Rocket Mass Stove Vs Conventional Wood Stove

As most of us know, a conventional wood stove loses alot of their effiency as the heat, along with the smoke, rises out through the chimney. Many stoves might be very efficient as far as their ability to burn wood, yet no matter how great the stove might be made, it still loses heat up the chimney.

The difference between the Rocket Mass Stove and a conventional wood heater is that the Rocket mass stove extracts most of the heat in the mass surrounding the stove and pipes, and stores it as thermal heat, before it exhausts the steam and CO2, not through a Chimney, but through a vent.  The thermal mass around the stove stores the heat, to be released later. The riser inside the Rocket Stove heater acts as a chimney, and by design it reburns the smoke, eliminating the need for a chimney, or it’s creosote buildup.

What are some of the pro’s of the Rocket Mass Stove?

  • Thermal heat lingers for several days
  • Heat your home with less wood than the conventional wood stoves
  • Fire burns clean — little to no smoke in exhaust
  • It can provide both quick and thermal heat
  • No creosote build-up in chimney
  • Vapor exhaust is steam and CO2
  • Super Energy efficient
  • Expense is lower
  • No two rocket stoves alike!  Your imagination is the limit for how it can look!


The Rocket Mass Stove and heater is economical and very efficient.  The question most often asked is this: “If my current wood stove is 75%- 85 efficient, it seems that the Rocket stove could only possibly be 15-25% more efficient than the conventional wood stove.  So how can you claim that a Rocket Mass Stove is almost 60-75% more efficient than the regular wood stoves?

The answer is simple.  Compare the temperature of the heat leaving the chimney (which is very hot with a large volume of smoke), to the temperature of the steam exhaust coming out of the Rocket Mass Stove’s exhaust vent. (almost room temperature).  The mass around the rocket stove extracts the heat and hold it like a battery, to release it slowly into the room up to 24-48 hours.

A conventional wood stove uses between 4-6 cords a winter, verses the Rocket Mass Stove, which uses about a 1 cord of wood a winter to heat the same size building, thus saving the environment and work in getting 4-6 cords per winter.

With the Rocket Mass stove, there are no dampers to worry about, no build up of creosote in the chimney to have to clean out, or to catch on fire, and and no smoke that comes back into your home through your windows.  The Rocket stove’s design automatically has a controlled chimney burn every time it burns, and thus it has very little ash.  When retiring in the evening, even though the Rocket Mass Stove is no longer burning, it will still be letting off heat all night long through the thermal mass that has stored the heat that is being released.

Where did the Rocket Mass Stove come from?

As far as we can tell, it was developed by the permaculture group (which call themselves “permies”) in trying to come up with a way of heating that was similar to the Masonry heaters, yet without the expense of the heaters or professionals needed to build them. So they designed a stove that could be done by a DIY.

Possible Con’s of the Rocket Mass Heaters

We have shared the wonderful pro’s of the rocket mass heaters, yet there are some possible con’s that we will consider for the moment of the rocket mass stove. 

1. One of the things that my wife (Debbi) had a hard time with was having a “barrel” in her living room, which she considers ugly. So we are looking into changing the appearance of the rocket mass heater, to get rid of the barrel look while maintaining the stove’s ability to have a clean burn.

2. The drawback to the Masonry heaters is their lack of having a lot of instant heat, for the times when you need heat quickly, and not 4-5 hours later when the beautiful masonry thermal mass starts to warm up. With the rocket mass stove, in order to get the instant heat as well as the thermal heat, the “barrel” needs to be partly exposed, which gives the instant heat needed. The goal we are trying to accomplish is to have a pleasant “look” to it that will heat the room with quick heat, as well as having the thermal mass heat for more efficiency. We are wanting the best of both worlds.

3. If you don’t get the dimensions right, the J tube won’t work right, and if the riser or the pipes aren’t in the correct proportions, again, you won’t get the right draw from the rocket mass stove, and smoke will back up into the house.

3. The theory of the rocket mass stove as promoted by the permies, and lacks the ambiance of being able to sit in front of the fire and watch its cracking warmth.

4. Because of the new design of the Rocket Mass Stove, it has a small “burning hole” in which most rocket stoves are designed with, and so you firewood must be cut into long slender pieces of wood.

We are working on possibly designing an internal j-tube/riser kit for the DIY’er, to help eliminate the frustration of getting the dimensions right.

Below is a link with Larry helping to build a rocket mass stove in a green house.

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