Wow, when you first built this I was very interested in the long time run of this, I love that you came back to it! Good job on the engineering of it!

You should show a timelapse of a couple of thermometers around the room starting at pre-ignition and ending at what is you're comfortable working temp. So we can see it in action.

I built a rocket mass heater in my living room about the size of a small elephant and you hit the nail on the head today. To make it work correctly at least, you have to run it for a long time and that means like you said, sitting on the floor splitting wood and feeding it. The problem is, since mine is so big, I have to feed it about eight hours a day for three or four days in a row, before it will maintain a comfortable heat level in my living room. Live and learn. As for my “shop“ heater, I made a very tiny rocket stove out of air Crete and ceramic and I just let it roar next to my workbench. I used a nitrogen cylinder for the primary chimney enclosure and a run an inch and a half 14 gauge square steel tube out the side across the shop and up to the stack. The horizontal section of that has corrugated tin “fins” welded where they touch the pipe and The whole thing works like a champ and heat things up lickety-split. Of course, it looks like hell, so if you have a wife or girlfriend, it probably won’t fly. Edit: A Simpler fix to prevent down-draft from wind is to drill holes on the vertical sides of the chimney pipe from the top down about 12 inches. Next, weld a cap on top, which prevents wind and rain and snow and birds and so on from going down in there. Next, weld a piece of steel pipe, open at each end over the termination .6 inches each direction, past the drilled holes. When viewed from the top down, it would look kind of like Darth Vader‘s stealth fighter, kind of. Anyway, all the holes you drilled lets the exhaust out, but wind blowing from the side or down can’t hit the holes, so it doesn’t become a problem.

Put a stove burner on top of the helium tank and then you could make soup and/or coffee while you're running the heater.

There's something unbelievably satisfying about watching you do this kind of engineering. Just love all the in-depth knowledge and thought you put into this, and the great way you communicate it. Keep it up, and cheers for all the videos so far!

From what I understand, super-heating the incoming air increases burn efficiency and insulating the exhaust flue improves the flow of exhaust gases.

Cool video. Got a couple of ideas/suggestions. 1. If you block of parts of the vent towards where the wind blows from, I think it will create suction instead of blowing air "backwards" into the system. 2. About the exit-baffler: Water Pipes etc. should have the valve-handle so that it's "across" when it's closed and "along" the pipe when it's open. That way you can see with a glance it it's open or closed. Might be an idea for the baffler-handle. Almost forgot: Peace man.

On today's episode, I'm cutting a hole in my goddamned roof. Balls of steel.

Very cool system. I built one last year. Quite different but exact same principle. You brought up where you get some smoke during initial start up... as you know these heaters are like an organism. They need a different kind of attention. I use a propane torch to pre-heat the exhaust. It primes them to get the heat moving in the direction we want. It only takes about 30 seconds and pretty much eliminates the smoke. I also have a damper just prior to exit of garage to close off cold air from cooling the heater down after a good burn.

7:15 - you get more than just steam out of the exhaust, it's just that CO2 is an invisible gas. The lack of smoke is a lack of unburnt carbon, which is indicative of a very effective burn cycle. If you wanted steam only, you'd need to be burning hydrogen.

Stoked dude and PERFECT timing. Just been offered a Pot Belly stove by one neighbor and a wood pellet stove by another and neither are rocking my world (although I am grateful for the generosity and thank God for good neighborly relations). My shop is 36 x 32 and very high. It's freezing in there all winter event though it's insulated. Miserable quite frankly and I don't like the idea of $$$ on a high end electric system. I have wanted to build a mass heater for a while but have been too chicken shit. This has given me some confidence. Thank you so much mate.

To code is always the best way. There might be a case some day where there's enough creosote build to cause a chimney fire (I know, rockets aren't SUPPOSED to, but...). Another: you sell the house. New homeowner puts in a standard stove. It's only a matter of time... Oh, and your on-off switch should have the 120V receptacle switched. Just because those small plug-in bricks are "Energy Vampires," drawing current (even if just a bit) whenever they are plugged in.

I've seen a few people talk about cold start issues. The 2 fixes I recall are having a bypass to get the chimney warm before starting to warm the mass or putting the chimney near the bell so it's heated that way. Folks generally want to keep electronics out of the mix because they're either using it as primary or emergency heat and in either case they want to be able to get it started in an emergency when they might not have power. Not an issue in your situation and even if it was you could run the fan with a power bank in a pinch.

I love how angry you get at the hippies every time you talk about this system, haha

I've been intrigued by these rocket mass heaters ever since I've come across them. I've watched all your videos on your heater. I like your more scientific and engineering approach to it. Thank you.

you did the right thing building it to code, because someday someone else might use that existing chimney with a different apparatus that produces much hotter exhaust.

I love the idea of a rocket stove. The trick to NEVER GET SMOKE INSIDE is to make a venturi tube outside encasing radially and parallel with the flu pipe with a enclosed motor at the top of pipe. This way you turn on the motor from the inside and never have to worry about going outside. This is only to start the stove when needed. This is the BOMB if you know what i mean. Good day too.

For the wind blowing into chimney problem, fit a H Cap/cowl, this creates vacuum as wind blows, so more wind, more vacuum

I don't know if you will read this, but I have had this idea for a long time though mine is different to a degree. I think if you use ceramic spray coating on the inside of your tank you will make it last for decades. This is the same principle used in turbine burn tubes. But I like the use of actual science and practical use of space, though I think you could have adapted a better intake design, and intake air to better burn, and also have a longer burn. I would love to collaborate with someone like you on a design. You have common sense and logic.

Interesting design. If you build another, do consider a batch box below the external intake.

I would add a "vertical feeding tube" for longer pieces of wood, that opens to the fire chamber and is air tight when the pieces of wood are installed.

Build a bypass chimney pipe you can send the exhaust through while you get it started and hot. Then when its hot switch the valve and send the exhaust thorugh the mass. It will give you faster and better stars.

Have you thought about putting a little fan on the helium tank to circulate the air and help warm up your garage more and faster? It also sounds like to should cobble together something to help split down your wood faster. This is my favorite rocket stove design I've seen thus far. I plan to build my own house and want to incorporate a rocket stove into the design.

Only improvement I can think of is a thermoelectric power supply for the fan running off the "waste" heat. Might still need the wall wart to get it started but once that helium tank warms up it would run itself. Yeah, I know, those are expensive. OTOH if you have enough scraps of the right metals laying around you can fabricate one. It won't be pretty but it will work. I don't *think* you'd have to bring in a cold sink from outside, should be plenty of energy available in the temperature differential between the tank and the room air.

I think the reason they say you can't use steel is because the heat causes the steel to oxidize very quickly. You might be able to just replace it every few years to prevent that.

HI new here. You got me at "Hippies don't tell you this!!!" I love these rocket mass builds, hoping to one day build my own. Its nice to see one made without the beads and couch attached to it! Thanks for making me feel "Normal" for loving these!

You could also put a Y joint on your air intake/fuel feed opening so that you can feed the fire without having to dismantle it every time. You'd need a cap for it and you'd still want to turn off the fan to get it going but it would make it a bit more functional. Might make it possible to construct some kind of automatic feeding hopper of previously processed wood too.

I did the very same thing a few yrs ago...but uninsulated dryer vent in-tube, Was in basement of two story so after basement got warm had some reverse ex flow problem when the heat rose up inside house so we just stayed in basement when it was real cold and the fan stayed on the intake. Great cooking on top of barrel with spacer so metal would not get red and warp?crack?melt? Lill cheat used wood chips I covered that was delivered in fall free., just added a expanded metal guide to hold em in place so my sticks were like a spacer that held the guide in place until all burned and started over..

Oh yes…we’ve had all kinds of trouble getting the old chimney to draw. Not even making the firebox smaller, could help it draw. Not even sticking a fireplace insert into there helped-it was a disaster. That’s another reason we bot a Liberator rocket stove + a chimney sleeve, besides how beautifully efficient these are. I used a drier vent to bring air into the air intake on it…& had to put a damper in that, to adjust air flow in. But maybe I’ll try insulating the intake, too…had no idea cold air would help the burn!? When installing the sleeve, I had to remove the recommended insulation wrapped around the sleeve, to fit it up thru the chimney, & simple-stuff it around the sleeve at top & bottom of chimney. Your cold air intake going direct into your feed tube, seems inconvenient….if it went into the side to of the feed tube, you could leave it connected, & be able to add wood more easily. Could even use a 4” pipe section to extend the feed tube then, allowing more sticks to be put into it, so you didn’t need to keep adding fuel so often.

I've never been more proud of my name being on something but also I'm glad to give you more considering the fact you're making wicked entertainment....you deserved to at least be recognized for that.

That is really cool. Gotta say getting something so efficient out of 'trash' is so Fallout/you lol

Nice job! Rocket stoves are a thinking person's woodstove... and even though mine is 4 years old... I keep messing with it, make new drawings, and will build version 2.0 at some time. There's so many innovations here on YT. I built a 6 inch flue rocket. It is a free-standing unit, utilizing a 55 gallon barrel. It is, internally, like the hippie rockets (hell, I am a hippie) only the riser is made from insulated firebrick (the most expensive component). The exhaust goes out of the bottom, and into a 15 foot long mass of cement blocks and crushed stone, at floor level. From there the exhaust goes up and out of the basement, through the wall, and outside through that super-expensive stainless insulated flue pipe, gifted to me by a friend (free is for me). My indoor flue temps, at building outlet, are similar to yours... rarely 150°... more often 120°. My stove is for heating my basement workshops, and the house above... the burn chamber is 8 x 8 inches,therefore, I can burn standard cordwood. From my experience, it looks to me as if smaller rockets are more efficient, and hotter... but most smaller ones are to heat workshops/garages, not entire homes... all I know is that I love using it. I was happy to get the insulated flue because condensation would run into the house, and black mung would run across the floor... at least it is water soluble, and cleans up with soap and water... I put a T flue pipe outside, at the bottom, with a seepage hole in a cap. This keeps all condensation outside. One thing I want to do is figure out an automatic lid, outside, that would close when the stove shuts down. I believe a lot of my mass heat is going up the chimney... and that the cold air, coming back down the chimney, cools the mass. I go through a wheelbarrow of wood per day. When I had a standard woodstove, I'd go through 3 wheelbarrows of wood... My rocket is on my channel if you'd like a look. The video is with the smaller 4.5 x 4.5 burn chamber... I've been using it for 4 seasons, and have had zero creosote buildup.

8:28 ...... HOL' UP

I Really enjoyed this video. The ONLY negative thing I can say is, When you glued the Roof flashing/tube/cone/witches hat.... (please insert your local slang for this product/implement/component....here & save us all the corrections from the peanut gallery) You went ALL the way around the flange underneath. I was Always trained to leave the lowest point (bottom of the slope) OPEN with NO GLUE or adhesive (meaning; you glue ONLY the TOP side, the LEFT side & the RIGHT side yep, only glue those 3 sides) Because, IF there is any build up of water/moisture/condensation, it has some where to go/leave/exit/drip & NOT build up or back up over the actual roof hole & leak back into the structure. Is this a rare occurrence? I think so but, by the time you notice the leak inside the finished space, there has been enough damage to the unfinished space, you still have an even larger problem. I have asked many an Experienced roofer about this ideal/ideology/preference.... & have ALWAYS been given the same answer; Yes leave the bottom open to allow drainage.

50 gallon drums.... not 500 gallon (oh them Hippies). LOL. Dude, this is just straight-up beautiful and just what I was looking for.

Very interesting, I hadn't heard of this until now. So rad!

A chimney installer once told me that you should never reduce your chimney to the outside since it created compression in your exhaust and and is counter productive to your flow! That way starting a range exhaust fan can easily reverse you flow to inside your house or your garage. In the case of a garage letting the door open could also cause the flow to reverse.

7:59 I lost my patreon-supporter-desk-name in an unfortunate schmelting accident

the hippies typically say you cannot make your combustion chamber out of steel, but i believe that's only true for the larger systems, like ones with 8" cross sectional flow area. the temperatures in those are much higher, and the steel will rust out within a few hours of running

Have you considered getting/making a small wood chipper to avoid having to spend the hour or so each day breaking up the fuel?

Hey, hippie here. If you have a predominant wind direction you should point the open end of you intake towards it, and the exhaust outlet away from the wind to generate a flow. If you want to get serious about harnessing that power also, you could stick a funnel on the intake side, and build a little venturi system on the outlet. That would negate the need for a computer fan, and possibly oversupply your stove with air (computer fan is a genius idea btw. I've heard that some fossil fuel based electricity generating stations preheat their intake air by drawing it down around the exhaust chimney, which results in such an efficient heat transfer that they then have to use fans to push the cold exhaust air out of the chimney. Similar to what you're doing here. Good Job)

it's all about the insulated chimney column to really get things flowing in the right direction, especially in really cold weather and especially when you add vertical column height to it. Also, the ease of operator input is more of a major factor than one might first imagine. pellet stoves will self feed for hours, a long feed pipe with scraps of sticks that will slide down on their own might also self feed for hours.

You could take the head off a lawnmower engine and bolt a small wedge to the piston. Then make a jig to hold 6 or 8” blocks to be split. Drive the engine with an electric motor and split very fast.

Hmmmm I may have to build that. As far as making sticks small enough to fit in there. Get a 14" bandsaw, and decide on the dimensions and start cutting. I probably already have 2 or 3 buckets of pen blanks that would fit right in there. One suggestion I would have is to add a small computer fan on the exhaust as well to ensure you get it going......

Fantastic update. Have been hoping to see a followup since the original series. Great work and chuffed that all your hard work payed off.

Have you considered adapting the burn chamber to have a pellet input? There are some gravity feed pellet systems. It could simplify the annoyance of having to tend the fire so much, but it would also add an expense in pellets. Nice design though.

hey man if you need free wood try those places that sell 4 wheelers or snowmobiles, the crates and packaging wood is thrown away

Congrats, you just invented an inter-cooled, super charged wood stove. This is quite possibly the most over-engineered wood stove in history in the best way possible

All of the information I wanted, well ordered, good video. Thanks for all of the effort and being so clear.

The comparison with propane at the end is a little misleading. It sounds like you're suggesting the rocket mass heater is more efficient than the propane heater because the rocket mass heater keeps the room warmer longer. But that's a question of convenience, not of efficiency. After all, you could create a propane mass heater if you wanted, and that would keep the room warm for a long time, too.

How do you remove ash from the combustion chamber? No matter how efficient the burn, there will be ash. I think I've worked it out, just like an ordinary wood burner, clean out the ash with a vacuum when it's cold.

Jairus, the flow issues with that stove are mainly because of the final chimney out of the house. Heat rises so the final chimney needs to be the highest point of the system (the interior of the house is a part of the system). When the air in the house gets warm enough and pushes out of the highest point, the huge volume of warm air in the house can cause the stove to draw backward because it is lower. Thermodynamics! The new chimney you put on will most definitely perform better, but it needs to be the highest point in the system to be correct and to give it the best draw and performance.

You could have also built a shroud that shielded the chimney from the wind, just an elbow facing sway from the wind. That would also potentially help with pulling the exhaust out by making a small vacuum.

You just breeze past that Austin powers Joke lol

pop an industrial EDF in your intake pipe! it'll give it so much power!

You should modify or fasten something to your intake chimney to block the wind from causing the Bernoulli principle backward flow

Great video, it’s amazing what you can do with the Tinman’s decapitated head...also, is wiggly a scientific term?

For a while it didn't sound like the furnace was vented to the outside. Was worried about Carbon monoxide poisoning. But you don't want the exhaust temperature too low. You want the exhaust to be hot enough to rise up and out. Get a CO monitor.

When you said you were going to do your outtake in front of the stove, but wouldn't because you felt like you were going to be burnt. Just had an idea, maybe put a cage around the helium tank to prevent anything falling on the tank? Air/heat could still go through, but would stop anything from falling on it and catching fire.

In case of power outage you should experiment with peltier wrapped around the cold air intact to power your fan

Any kind of steel used in the burn chamber is doomed to failure. The kind of heat created by a system like this will create spalling of the metal. Were you to take your system apart, you might find that significant erosion has already occurred. Masonry or refractory materials are the only thing capable of standing up to the extreme temps of a highly efficient wood-burning device, over numerous firings. Also, there is a simple bell design, with metal inserts in the top, that would take up about half the space of what your unit does, and give off just as much heat.

I really enjoyed watching you make the heater, glad to see it’s efficient

Add a rotating chimney exhaust tip that the wind turns like a weather vane to prevent downdraft. If made correctly you could use venturi effect to create draft when the wind is blowing.

One thing you did not mention is carbon build up in the heat exchanger and the exhaust pipe. Because the piping following the burning chamber is so cold the residue carbon will condense before it can burn. These build ups, once big enough can burn off and turn your exhaust red hot, so either clean it sometimes or be aware of a possible run-away.

ever thought about adding a waste oil burner to the system? add the oil once you've got the fire going.

How can you clean out the ashes and creosote that would accumulate in the exhaust chambers over time?

As far as your exhaust problem. You should be typically. 3 foot higher than your roof Peak so you don't have the wind draft problem. For a regular wood burning stove anyway

Man, I would love an update on your heater to know how it's holding up and if the steel held up or not. Or just an update in general, you haven't posted in a long time

If your worried about the cold dense air pushing it's way back down the chimney it seems the best place for the exhaust to exit your garage would be near the floor. This would also condense the warm moist air in the system if any at floor level so it wouldn't run down into the system. What do you think?

He doesn’t like hippies, like Eric Cartman. The Cartman of rocket mass heaters.

I don't know if you've ever heard of a HAHSA (Heat and Heat Storage Apparatus) but the concept was introduced in Mother Earth News a few decades ago. Initial investment would be higher than this system since the home heating is done through hot water which required a well. This fed into a small building (6x6 if I remember right) with a woodstove in it. The pipes went around the woodstove and the entire building was filled with sand which acted like a heat sink. It would keep an entire house warm by all reports. Sounds like your system is n ot only cheaper but more efficient. =)

Lol buy the book, there are 2 and they talk about all those things the hippies don't tell you about...like a bell mass. Great stuff.

For more ease of use at the expense of some cash ether find a small used woodchipper or grab some bags of charcoal/wood stove pellets when they go off season and the stores are trying to clear them out Or there might be a local woodworker or cabinet maker that wouldn't mind you hauling off some of their saw dust and small scraps

Wow, it looks very much like a Russian fireplace. I got plans for one from the Missouri Agricultural Extension Office website. Use a sloped feedramp for automatic feeding of the fuel.

I'm going back to watch the series. So, ignore this post if you address the question. How would this compare to a normal wood burning stove?

This is why masonry heaters are so much better. Load up the firebox, light a match and walk away. No Hippies required.

I would recommend double wall pellet stove pipe because it has a stainless steel liner in it. It comes in 3 and 4 inch sizes. Also 6” triple wall stove pipe could be very useful here. but, good job looks good!

you should reweld the handle turned 90° cause than it indicates correct, if the valve ist open oder closed.

TYLER GOT WATER OUT THE DITCH!!!

Excellent. And you did a great job on your overkill exhaust improvement.

Just thinkin, if you put a 90° bend on the exhaust and point it down wind, would it help create a draw?

AWESOME stove! But man, the handle on the butterfly... 😅

I think you have done a good job here I think the reason you can use metal in the burn tunnel is you have a micro system, I think if you had an 8 inch system metal would not last. I don’t think you give the hippie’s enough credit, I did laugh when you kept bringing them up because I think too many of us are over the top on political correctness, I Have been to Ernie and Erica’s place and seen their rocket mass heater they are probably the most experienced builders alive. And they are both extremely well educated about fire and thermodynamics you keep mentioning. Anyway I love the video thanks for sharing, thumbs up from me dude!

Just a suggestion for this: I seen fans that run just from heat exchanged from copper fins. Use them and it could be zero point energy fed. also maybe for a future project, think about a sealed unit that has copper tubing and 50/50 glycol water mix. In floor heating works with this same idea. The problem is sealing it and making is safe enough. But same idea, the water feeds into the bottom, hot fluids rise and out the top to heat the floor, then back in again. But teaking out a floor probably isnt big on your list either heh. So anyone else have a plan with a dirt floor garage might be able to though.

That's a really nice stove, but as much as you poke at the "hippies", your stove doesn't operate properly without a fan....Maybe because the main mechanism for the flow of air is the insulated burner tube that accelerates the air in the system so you can do those up down bendy things with the flue pipe and still get proper air flow. I'd bet money your stove would work better if you'd used a simple insulated riser instead of your complicated contraption. I do appreciate the hard work it took to do this and the high efficiency of the operation though. Oh, and if you separated the feed tube with the air inlet you'd be able to make it so you can put much longer pieces of wood in without impeding air flow.

This is sooooooooooiooooo awesome

If you add a thermocouple to charge a battery to run the fan, you can take it entirely off-grid. Dunno if the complexity and cost are worth it, but you might find the idea amusing.

You could probably use peltier effect plate to run your PC fan once it gets warmer enough so that the system is keeping itself going instead of puling power from the wall

I hate to tell you this, but, I think we’re on the same wavelength. That being said, I’m old and had trouble keeping up with you. Is there any way I could get a semi-detailed drawing? You’ve done a great job. Thanks 👏🏻👏🏻

Nice to have wood pellets as an option for those days you do not have time or sticks.

I was concerned about creosote build up in the heat exchanger but I see in another comment that you have pulled it apart and haven't seen that to be an issue. Makes me wonder why I have to clean my chimney twice a year when it's a straight shot up.

Nice setup. That dense cold air is the ticket.

Would insulating the drop pipe from the rockets tank into the mass reduce the amount of instant radiant from that amount of surface area and put it into the mass possibly helping the draft a little in the process. The surface area of the drop pipe could be 1/5th of the surface of the tank itself (not going to take time to do that math). Maybe a header wrap or the fiberglass stuff you used on the primary burn chimney and leave the joints exposed so you can still remove it easily. Although I think your new outlet chimney can change the issues you had. I would love to see it work without the 12volt fan except for start up times. Also dollar store aluminum tape can hold up to 700F I use it on my woodstove outlet flue joints before the masonry chimney and the joining of the flue to the stove since everyone's 8 inches isn't exactly the same (0.o) and I didn't want to build a shim. I take this off twice a burn season at the stove to clean things and have seen it peak to 700F when I fire it off sometimes before I engage the bypass to the cat chamber and all is well with it. I know what you mean by scavenging all the heat my stove full burn the box is +-500F with the cat up to temp 1200-1400F my flue temps drop to 250F versus 500+ with the bypass open at full burn. 700lbs of cast iron and tossed some old chevy heads on it for good measure. I might not be as efficient with the wood but for a woodstove I think that is pretty good being my flue temp gauge is only 3 linear feet from a 1400 degree cat the design makes use of expansion just after the cat there is a chamber before the flue this somehow lets a majority of that 1400F radiate through the walls and top plate and only put 250F up the flue that is internal smoke path temp not wall of flue temp. Since I have an outdoor masonry chimney I wouldn't want any less than 250F going out.

Love it thanks for the update Ultimate upgrade auto feed and start up so you can program it to start for an hour or two every 12 hours

Please add this one to the playlist!

Could you use wood chips? Then you could solve the hour long cutting wood with a crusher

thanks for the tips! upped my game for sure... now it's time for me to learn to weld.

if you want better flow you can make a weather vane type chimey/inlet caps so that the inlet is always on the high pressure side of the wind and the exit is always on the low pressure. but im a hippy so you prob dont wanna take my advice!

i like your overkill protective measures. the problem i see is the steel core of your system.. if it is surviving as you say then you arent getting as hot of a burn as would be desired. but hey it’s still going to be better than a standard wood stove..

I love your style. Very well made video