Rebuilding and Improving a ROCKET MASS HEATER

The rocket mass heater in Skyhouse at Dancing Rabbit Ecovillage was in need of some repairs and improvements. It was at least 15 years old and had always had some issues with efficiency in heating the space it was supposed to. Mark Mazziotti, of nearby Red Earth Farms, was hired to do a total rebuild of the stove because of his experience in building rocket stoves and mass heaters. I happened to find out he was doing the rebuild and asked him if he would help me make a video about the project. It's a little longer than some of my usual videos, but it's interesting to hear the thought and planning Mark put into the rebuild.
Mark wants me to add that he miscalculated his estimate of his experience in natural building. It's more like 15, not 20 years of experience he has.
/ hardcoresustainable
/ hardcoresustainable
hardcoresustainable.com
#rocketmassheater #rocketstoves #cobstove

[@jessicat3951]

Thanks for showing and describing some cons to how these things can be built and need to be maintained. It’s hard to get really honest information about RMH because everyone is evangelical about them. It’s nice to get some straight dope!!!

[@joeyork9891]

Great update..... obsessed with rocket stoves and mass

[@maryrock9136]

Mark's mechanism for cleaning out the engine is a great idea!

[@alx81]

Mark has very kind eyes!

[@itanc1]

Really nice dood! With you on the ash port all the way, always seemed a must have to me…all of mine have them. Cheers fella

[@wulfclaw4921]

You did a fantastic job on this video. I love my Rocket mass heater ! Wulfy

[@l0I0I0I0]

Nice! I've been watching dozens of the RMH vids. Like what you have done!

[@l0I0I0I0]

Any idea how to make a huge one for heating a greenhouse? Ultimately that's where I'm going with it. You did say repeadly only 1000sf max.

[@jeancampbell4341]

I love your rocket stove! Well done

[@13thravenpurple94]

Great video THank you

[@RushHourRecords]

Thank you so much for all the info mate! Your legendary. Ive just found ur chanel. Loving it so far and have subscribed!

[@HardcoreSustainable]

Glad to have you watching!

[@locallivingventure3300]

I find with my RMH that it's ideal for when I want to be gone all day, so long as I have 2-3 hours to tend it before I go. With my wood cookstove that heated my home before that, most of the heat would dissipate and it would be chilly when I got home. With the RMH, a wave of heat greets me when I get home at the end of the day. Now, if it's sub-zero out, this may not apply. You may want to keep the stove going for several hours in that case, but anything above 10-20 degrees F, it's awesome for leaving all day. You can see mine if you search for Chelle Lindahl's RMH by Possible Media. Also, we built mine with fire brick, not red brick, I think that matters!? Oh, it looks like the feed tube might be the yellow fire brick here? And, my chimney is fire brick as well, wrapped in rock wool, not welded steel.

[@locallivingventure3300]

PS the clean out is pretty cool. I find I have to clean out the ashes from the feed tube every other burn or so, but I use a piece of wood as a scraper to pull it down the horizontal tube to the feed tube pretty quickly and easily, and then took a larger than usual size can, the size of maybe Progresso soup, and flattened one side, to scrape along the bottom and scoop up the ash, works pretty well and is quick, but this is schnazzy! :-)

[@HardcoreSustainable]

I guess that's a perk, but then you are heating the house while you are gone and that doesn't seem as efficient. While it's nice to come back to a warm home, it seems like a lot of work for heating the house while you are gone. I can get my house warm in 15 minutes with a wood stove, though on a sunny day, the sun heats my house during the day. I could see the RMH being more useful for staying warm overnight, which is a problem with my wood stove. I wake up at 6 am and my house is colder and I have to light another fire, but that would be less true if my house was better insulated.

[@harbel8088]

What a quality work

[@rogerdodger5415]

What a good video! He explains and describes why you do different things. Just what I need. Thanks 🙏 🇺🇸🇺🇸🇺🇸😎👍🇺🇸🇺🇸🇺🇸

[@HardcoreSustainable]

Glad you liked it. Thanks for the comment!

[@taksojdet]

Good man 🔥

[@johnsorrelw849]

Great video of a neat, simple technology. One caution... If you are cutting bricks, consider wet sawing to control the silica debris. I wouldn't rely on respirators alone for protection (and they don't really work for us bearded folks). Also, you want to keep others from exposure to the hazardous dust, which gets airborne when cut dry.

[@craigwagner763]

I was also under the impression that a metal burn chamber was a no no.

[@HardcoreSustainable]

Seemed to be with the old version of this stove.

[@gjh42]

A 6" J-tube may be tricky to clean out unless you are petite. I find that my 8" J-tube is super easy to clean once a week with a tuna can flattened on one side and attached to a short handle. I can pull ash from the far end, and in the same motion lift it out and dump in the ash can. Since there is no soot in the burn tunnel, I do not get dirty beyond a dusting of mineral ash.

[@saltydecimator]

AAAAAMAAAAAAAZIN!!!!!!!

[@johncees6178]

thanks for the vid. i also have been building rocket stoves for many years. i make small ones from stove pipe for ice houses to large ones like yours. i offer some observations for your future considerations, rocket stoves are like diesel engines in that more air is ingested than is burned. the un-burned air is referred to as ballast gasses by the Russian stove builder Kuznetsov and hinders the draft of the stove. the barrel can be thought of as a heat bell or dome. adding port holes to the combustion chimney (as per kuznetsov) significantly improves the draft of the stove. i now often use an uninsulated chimney with ports and find performance significantly better than the insulated but un-vented combustion chimney. the real engine of any stove is its final chimney and one inside the heated space is better than one outside as a warm chimney draws better, but i digress. any stove can be as efficient burning as a rocket stove provided it gets enough air. rocket stoves shine because this is achieved with a small fire such that it can capture this heat more readily in the heated space before losing it to the final chimney. this is where mass helps; the larger the mass the larger the fire u can use. as such, i find i am moving more often to batch fire mass stoves for my own use as if find the continuous feed requirements of the rocket stove tedious. a fire twice a day with sufficient mass and bells to capture the heat designed using Kuznetsov principles is much more tolerable for continuous use as a primary heating source. the point of all this tho for your rocket stove is to provide venting in the combustion chimney (whether insulated or not) that allows for the passage of ballast gasses to greatly improve your stove's venting performance. this i know for u is closing the proverbial barn door after the horse has left but might be useful for your builder to experiment with for his future builds as this really is a marked improvement. hope this is received with the good will that it is sent as i am a great fan of the rocket stove diy principles. all best, j

[@HardcoreSustainable]

Thanks for the great ideas!

[@johncees6178]

hi steve, thankyou for your questions; i see on rereading my post that i was not as clear as i thought .allow me to do some labeling; lets call the wood feed, the feed tube, the horizontal burn chamber the burn chamber, the chimney inside the 45 gal barrel the combustion stack or stack and the final chimney the chimney. it is the combustion stack that i modify . like the pipe inside a car muffler , i drill it full of holes. this allow s the ballast gasses a chance to pass from inside the stack at lower elevation. on an 8 in stove, the total amount of holes drilled in the stack would add up to say a 1/2 in wide continuous slit the full length of the stack. this seems counter intuitive but has been tested by me and the principle is practised and proven by kuznetsov in his masonry stoves.the stove breaths better and the temperatures achieved in the stove are hotter. my current 5 in stove improved from 400 degrees measured at the top of the barrel to well over 500 f. i recommend u build a cheap rocket stove from say 3 in stove pipe and a 5 gal can to prove the point. concerning the chimney, all i meant was that a chimney that is mostly inside the house exiting the roof is better than an exterior chimney and if one is forced to use an exterior chimney that it should be insulated as the chimney is the real engine of any stove. i challenge the idea that this j tube/barrel design is the stoves engine once the barrel is added as the barrel acts like a brake on the stove,(if the so called thermo syphon action is present then adding the barrel "bell" should increase the stoves draft, it does not) build your practice stove with the j tube and barrel only,remove the barrel light the fire and see how it roars, even without insulating the stack (the insulation is a waste also), place the barrel as per the stoves design and note the diminished performance. i argue that the barrel is a heat trap identical to the heat bells of masonry stoves and if you don't need the high temp quick radiant heat, it and the stack can be eliminated entirely. concerning the stack, i recommend that it be heavily made to function as additional mass in the stove just where it is most useful. additionally , if in use the heated space becomes overheated before the mass is charged then reduce or insulate the radiant steel of the barrel or replace the barrel entirely with a masonry or earthen equivalent. i hope this is useful. and please,test all i say as i am the only one i see practising these ideas in the rocket mass heater community and expect u will be challenged on these points. all best , j

[@mudbloodbuilds]

@@johncees6178 could you explain further why adding these holes is beneficial? Without insulating the heat riser, is the danger not that the temperature between the riser and the barrel will equalize, hurting the draft effect? How do the holes improve this? And could you drill holes into a brick or ceramic riser?

[@johncees6178]

@@mudbloodbuilds drilling holes in the "combustion stack" is to allow cool un-burned gases (called ballast gas) to pass out of the combustion stack early thus not robbing the properly burned and heated gases to it's energy. this is based on the work of the Russian stove builder Koznetsov and has been used by me successfully on several stoves with both standard stove pipe and masonry combustion stacks. Look Mr. Koznetsov up yourself on you tube, he still has a few videos up and you can get his website from them. With brick I simply leave mortar out on one or two joints vertically so gasses can pass. As I have said, do an experiment in your back yard with a barrel and some stove pipe or even bricks with out mortar to prove the point. As soon as u add the bell barrel upside down over the combustion stack, the stove nearly dies. It's real engine is the final chimney at this point as the cooling of the barrel really adds nearly nothing to the draft. My stoves all breath better with is modification and it would not be in vain to conduct this experiment for your self before committing to your final build. hope this is helpful. happy stove building.

[@mudbloodbuilds]

@@johncees6178 thank you for your thorough explanation. very curious about this. will proceed with experimentation..

[@MatthewByrd]

This is an awesome video. I'm wary of cob building here in FL though with the hurricanes and sideways rain we get. Maybe when I sell my house and move north I can build one of these. Very cool stuff

[@zaneymay]

We live in Northern Florida also in the big bend area. We are building a house soon and plan on building a MRH. Since it's inside the house the extreme moisture, etc shouldn't effect the cob.

[@MatthewByrd]

@@zaneymay Yeah I was concerned with the cob walls on the exterior. Even with the lime plaster I worry that when the crazy sideways rain shows up, it'll just melt.

[@zaneymay]

@@MatthewByrd oh I thought you were just talking about the cob on the hearter it self. Yes, I would not do cob that is exposed to the elements in Florida.

[@HardcoreSustainable]

You could do interior cob in Florida. As long as it's protected, it will hold up to hurricane force winds. I definitely wouldn't recommend it for exterior. Some people at Dancing Rabbit in Missouri do earthen plaster exterior, but they have to coat it with linseed oil every couple of years, have a large overhang to protect it, and still it erodes in time. Earthen plaster is used in a lot of rainy places, they just regularly reapply it. Everything doesn't have to last forever if it's biodegradable and just needs a little elbow grease to be renewed. I'm going to be posting a video before long about an earthship being built near Sarasota. They used a lot of concrete on both exterior and interior, though. The other issue with cob in Florida is the lack of clay--something we have in abundance up north. Maybe there is more clay in northern or central Florida. Sand is abundant though, so if you could find clay, you'd be set. I would think lime plaster would be fine as well since it is pretty much weather proof and will hold up to driving rains. You just need lime and sand, maybe some fiber for that.

[@comptegoogle511]

You can use perlite as an aggregate to make your combustion chamber and chimney. This way it would heat up very fast and isolate it resulting in fast efficient burning when you start it.

[@craigsymington5401]

I like this, the builder has some experience, from my observation. I've found a bit of air through the cleanout aids in the complete combustion of the carbon on the floor of an uninsulated feed tube, but a sliver of a gap only once it's on "full noise", or you get smoke backdraft. I've also experienced that the lid needs a more variable flow regulator depending on temperature, wind and fuel quality. When you get the air/fuel ratio right, there's very little cleanout. Avoid paper to light the fire...Have a way of closing off all air flow at the end of the burn cycle, keep the heat indoors...

[@lancerudy9934]

Very nice

[@videobob6789]

how about a million thank you

[@bpetnoi1472]

So the combustion chamber is now fire brick to prevent burnout and you are just using a short metal feed tube and cap?

[@edwallace827]

I hope you don't mind if I borrow your quote "sequestered sunlight" what a great description of not just wood, but all forms of fuel we use on this planet, from fossel fuels, to the food we eat. It's all solar powered!

[@voidisyinyangvoidisyinyang885]

I think what he was getting at is that a mass heater uses radiation heat instead of convection heat as with a normal wood stove. So infrared heat is the same as the solar heat from the earth.

[@voidisyinyangvoidisyinyang885]

the ash clean out reminds me of the Chinese Kang bed stove heaters. So you feed from underneath and then on top you have your wok. That seems more practical - instead of just using a gravity feeder - since you have to feed it anyway. Might as well cook on top of it while feeding the stove.

[@HardcoreSustainable]

I want to build one of those as part of a wood fired composite stove I plan to build soon. It will have many different cooking stoves together in one thermal mass: a place for a wok, a flat iron surface for flat breads of all kinds, a grill for charcoal cooking things like satay, tandoori, and kebabs. It will be all the versions of fast, hot, minimal wood cooking. It'll be outdoors though.

[@voidisyinyangvoidisyinyang885]

@@HardcoreSustainable Sounds like you can do it!

[@justinw1765]

I really like these RMH's, but I wonder for the folks who have plenty of sunlight on their property, why aren't more people collecting Solar heat and piping it through the windows? You can have an immediate heater for daytime use that just uses insulated boxes etc outside that collects Solar heat directly, and pipes hot air in. For nighttime, what you do, is have some Solar panels that connect directly to nichrome wire (no expensive lithium batteries, no controllers, etc), wrap that nichrome around some copper pipes and then put this in some good heat absorbent material (a mix of say compressed talc powder and aluminum blocks or the like in a clay pot), insulate it very well (preferably medium vacuum), and then at night, you take off the insulation from heat "battery" to let it warm up the house at night. (It is probably more ideal to have individual, smaller heat batteries placed in different rooms than one really large one). The nice thing about these is that they are easy to build, maintain, and there is very little tending to it unlike with a RMH that needs a good amount of attention. With the dual Solar system, you just turn off the fan and put an insulated flap down over the ducting hole that is placed in a window insert, and then take off the insulated containers for the heat batteries, then reverse during daytime.

[@gjh42]

Rocket mass heaters can heat any reasonable size of space as long as it is fairly compact. Heating bedrooms at the far end of a hall is a stretch. Sizing the RMH to the space is key; making it larger than necessary will just mean that you don't have to burn as often, while a too-large wood stove is a hazard as it must be damped down to smolder frequently.

[@mobilecivilian6124]

Pretty bad ass mouse trap too.

[@richardcooney7789]

Where I live in Canada, All heating systems must be ULC or CSA tested or you cant get insurance or a mortgage . where is this and do you have insurance and a mortgage ?

[@martinahlstrom8037]

The effects on the metal is called spalling. This happens with many non-heat resistant metals in a high oxygen / low carbon atmosphere at temperatures above 700 °C. Stainless steel is one way to go for metal burn tubes and heat risers.

[@j.hanleysmith8333]

Nice video! Thanks to you both for bringing and promoting these technologies to the world :-) I'm curious if the floors of these houses generally have an insulative layer between the living space and the earth? I feel like this is especially relevant to the mass and the radiant floor heating. Thanks again!

[@HardcoreSustainable]

Yes, our earthen floors do have an insulation break between the ground and the cob of the floor. Skyhouse has strawbales (which I wouldn't recommend) and I have light clay straw (which I would only recommend if you lay down a base and use the floor for a year or more before laying down the finish coat. It compresses a lot). Others use perlite or rigid foam.

[@j.hanleysmith8333]

@@HardcoreSustainable thanks!

[@timhaugen6410]

I'm not trying to outsmart simplicity, here, but if you have some dough to blow, could you run tubing around to places you'd want heat? Your set up looks like it has plenty of room for coils of tubing full of water. Thanks for the video.

[@gg-gn3re]

@@timhaugen6410 basic in floor heating..?

[@voidisyinyangvoidisyinyang885]

Only you don't want to lose your ELF Schumann resonance from Earth floors also.

[@l0I0I0I0]

I love what you have done. I have some clever tweeks I plan to use on my RMH to build upon these systems I've been seeing. I won't spam you however. Lol 😂. Job well done! One question however. Why not route intake air from outside? If you pull air from inside, your creating a huge house vacuum which sucks cold air from outside countering the primary objective of heating your home. Houses are usually slightly positive pressure. Also cold air is more dense meaning more oxygen thus hotter more efficient burn. Same goes for actual jet engines, the engines perform better in cold air for the same reason. Down side might be more work ducting air in and higher temps potentially reducing life of stove.

[@HardcoreSustainable]

I'm not sure why no air intake from outside. I know most wood stoves are set up the same way, though some have the option to duct air from outside. I think it's just assumed there is some draft in a building and that fresh air is needed as well to keep the air inside fresh. You could also do an air heat exchanger for keeping air fresh.

[@l0I0I0I0]

@@HardcoreSustainable I like the air heat exchanger idea. I have bounced the idea around and investigated some designs. But from theory cold air sneaking in the cracks brings in ...well..cold air. Lol. Thank you for sharing your build! I was just discussing some of these designs with a man from church this morning.

[@elainepreps9669]

Interesting 🤔🤔🤔...😊👍

[@davehoover8214]

Was I seeing something wrong? Were you using some of the cob as brick mortar? Thank you for the video.

[@HardcoreSustainable]

Yes, he did use the cob as mortar. Since it's not going to be out in the elements, it works fine as a mortar.

[@4115steve]

Thank you for sharing this life saving technology and not charging for a dvd like others do. I don't get why people want to charge for something like this.

[@HardcoreSustainable]

I don't hold it against people for wanting to make something for the time they've put into learning a skill. In the past people had other ways of getting compensation for passing on their knowledge, such as building community and mutually supporting each other. These days you can just watch a video and get information and the person who put the time in is just donating their investment in learning a skill and their time in creating a video. And making a DVD alone costs a lot of money. But I get what you are saying.

[@MatthewByrd]

Also I forgot to add, the ash would be pure carbon too which you'd just use as a fertilizer as it's great for veggies and improving soil quality

[@Dollapfin]

Matthew Byrd yeah no it would be pure potash and some calcium. It’s also great fertilizer. I think you just mixed carbon and potassium.

[@voidisyinyangvoidisyinyang885]

don't forget the humanure compost - it's a growing business in Africa now. Sanitation collection business. MIT students started it.

[@jonothandoeser]

@@voidisyinyangvoidisyinyang885 Takes a while to make humanure though.

[@voidisyinyangvoidisyinyang885]

@@jonothandoeser yes Two years in northern climates. Check out Sanergy in Africa - lots of youtube vids. Not sure how fast their turn over rate is for a product.

[@jonothandoeser]

@@voidisyinyangvoidisyinyang885 In moderate climates a little over 1 year. Maybe be faster in hotter climates.

[@rafaelborrego36]

Why dont you feed wood thru the ash door? Does it burn diferent?

[@HardcoreSustainable]

The good thing about top loading it is the sticks feed themselves into the fire. If you loaded them from the side they would have to burn backwards toward the air intake.

[@rebeccamiller3600]

Do you sell them? Or do you know anyone who does? Widowed don’t think I could do it by myself

[@HardcoreSustainable]

You could find someone to build one for you. I know Mark does projects like this and travels for them, so he might be able to make one for you.

[@SXMSXMSXM]

Thanks. A question: at 9:28 min. Can a ceramic waterpipe chimney cope with the heat right after the combustion chamber? I,d like to know cause i have one to be used for it.

[@HardcoreSustainable]

I don't know the answer to that for sure, but since one is used in this, I think it's okay. You might look at what temps ceramic water pipe can endure or if others have used them.

[@SXMSXMSXM]

Did you not look into this before building? You think it is ok since it is used here. Is it not your own build? I will see how this ceramic waterpipe of mine deals with a campfire before using it as a chimney.

[@HardcoreSustainable]

@@SXMSXMSXM This is a documentary of this project that someone else carried out. I'm the one filming it. I've never built a rocket mass heater before. I'm pretty sure that the mass heater is still working and now it's been in use for a couple seasons. I guess the question would be, is the pipe still intact or is it cracked and falling apart by now. You'd have to open it up to know. Someone who knows better than me would be able to say if this pipe holds up to high temps. I'd guess so since it had to be fired at high temps to be made.

[@SXMSXMSXM]

@@HardcoreSustainable Thanks for your reply. I have watched some more documentaries on this/ your channel. Interesting topics. Subscribed!

[@gjh42]

Terra cotta pipe can take high heat, but fast heat as the heat riser sees on startup will stress and crack it. As long as it is held in place by the insulation jacket it will probably be alright, but dense materials are not ideal for the riser. You really want light, low-mass insulating material for best efficiency.

[@briholt100]

I have a newbie question...with the heat riser pointing up at the inside of the barrel top, won't that barrel top disintegrate in a bit?

[@HardcoreSustainable]

You mean disintegrate from the heat?

[@briholt100]

@@HardcoreSustainable yeah... I've read that using metal inside will work for a few years but eventually metal disintegrates But I get the need for having the barrel, and obviously based on your good vid you can replace it. But I wondered if there was a plan where the top of the barrel was protected from the direct blast from the riser

[@HardcoreSustainable]

@@briholt100 I'm not sure. I think everything was shown in the video, so if you didn't see something there, it probably isn't protected.

[@briholt100]

@@HardcoreSustainable I was just asking 'in general'. Thank you for your help

[@craigsymington5401]

@@briholt100 Valid point, I've seen others simply weld a thick plate over the "hot spot" to increase the lifespan of the barrel, others use stainless steel, which is preferable. Output from an efficient rocket burner is theoretically CO2 and H2O if the temps and gasses mix in the correct temps. There are local factors in play, height ASL, timber, and atmospheric pressure, air humidity. However, the basic science is the fire triangle, aiming for full combustion and max heat extraction AFTER combustion.

[@peaceofearth]

Quick question for you... We are also in Missouri and this is our 2nd winter with our rocket mass heater. We are cleaning out a quart÷ of ash from the burn tunnel every day and cleaning creosote from the clean-out under the exhaust pipe- about 1-2 quarts a month. Does this seem excessive to you? We see other RMH videos and people brag that they have hardly any ash... Just wanted to check with another Missourian to see if we are ok or need to re-assess. Appreciate any guidance you can offer! ❤

[@HardcoreSustainable]

I don't have any specific guidance for you as I don't have a rocket mass heater in my house. I have a small wood stove. I would guess it really depends on the type and quality of wood and how much of it you need to burn to heat your space. Obviously a bigger space in a colder winter is going to need more fuel to heat, and produce more ash. Some woods are better, denser as fuel and some leave more residue or ash behind, and depending on their quality (more punky or not rotten at all) they can burn differently. I'd think if your firebox is getting a good flow of air and your fuel is burning like it should in a rocket stove, you are probably doing it right. Creosote buildup can be the result of lower burn temps, so that could be an indicator something is wrong. But that being said, creosote is a reality of wood heating. Sorry I don't have any specific numbers and guidance. The people at Skyhouse using the RMH would know better, but I'm not in Missouri right now. I never trust everything I see on KZbin because people will exaggerate their success all the time to get people's attention, to get more respect, or because they don't really know what they're talking about.

[@Dollapfin]

What about cob instead of perlite as insulation. My idea is to get a cob high in clay and form it around the central flue. The cob would be straw but have lots of sawdust mixed in. When the sawdust burns or pyrolyzes, you’re left with ceramic insulation. Viola.

[@voidisyinyangvoidisyinyang885]

My guess is that perlite has much higher insulation value than just clay. Some people use rock wool. Same reason that cob houses don't work well in very cold climates - but instead better to use insulation.

[@Dollapfin]

Voidisyinyang Voidisyinyang in the year following this comment I actually built an outdoor batch box rocket stove and I’m working on getting it to be an efficient pool heater. I used cob for the firebox and it is actually extremely insulative once the organic matter burns out. The riser was made with perlite clay. Works pretty well so far. Still adjusting the primary air as it chokes itself out pretty hard, but it’s going good.

[@voidisyinyangvoidisyinyang885]

@@Dollapfin Impressive! You could upload a vid maybe.

[@Dollapfin]

Voidisyinyang Voidisyinyang I might. Never really done that before. I will try once it’s all tuned up.

[@jacoblevin8567]

Is there a way to maintain fire automatically? Like putting long sticks?

[@HardcoreSustainable]

Not sure. I'm sure someone's tried it. Maybe a hopper of some kind.

[@kenwatanabe2599]

think pellet stove.

[@jacoblevin8567]

@@kenwatanabe2599 thanks, but im trying to do the same with wood sticks...

[@kenwatanabe2599]

@@jacoblevin8567 this video may have your answer kzbin.info/www/bejne/e5rMk52HprSapc0

[@jonothandoeser]

@@HardcoreSustainable Yeah, I've seen quite a few of these with hoppers and wood pellets. That solves the need to feed the stove every 30 minutes. But then, well constructed rocket mass can be fired for a few hours and continue to heat the house all day, after the fire is out.

[@tylerbob4853]

How do you obtain homeowners insurance with a homemade rocket stove as now any home has to have a U.L. certified wood stove.

[@HardcoreSustainable]

You'd likely just have to pay more for a special policy. Not many of the houses at DR have insurance.

[@craigsymington5401]

According to my research, that is a sticking point, many states and insurers don't allow any "DIY" scenarios of any combustion variety. The "liberty" is UL listed, it's steel and has some clever designs, but isn't durable as a primary heat source. It allows several fuel solutions, including pellets.

[@rexgoliath4032]

There is a difference of meaning between anxious and eager. I think both times you meant to say eager.

[@HardcoreSustainable]

Thanks for the info. I guess I never really knew of the nuance of that word being particular to unease, though the dictionary shows eager as a synonym and says anxious means "wanting something very much, typically with a feeling of unease." Eager is probably better.

[@Pilot333]

I like more to actually see IT... instead of seeing the speaker.... ;-)

[@HardcoreSustainable]

Not sure what of the stove you didn't get to see.

[@peterzappe6197]

Holy crap. How much coke did you do? Sweet stove. Sweet house.

[@HardcoreSustainable]

Why would you ask about coke?

[@billwoehl3051]

Here's mine, uses water for the mass, and an ash tray: kzbin.info/www/bejne/raiaeqSMidNqlc0si=OXUEOLjB2m-QDI1G

[@oasibioserendipity2026]

Hi there, I found your video interesting. Why do you say it's not ideal for people who are not at home all day? Your Surname seems to have Italian origins! Greetings from Italy here

[@HardcoreSustainable]

I'm not Mark, the guy in the video, but I know that rocket stoves like this one need to be fed throughout the day to continue heating. You can't just load it with a bunch of logs and leave it like with a wood stove.

[@gjh42]

RMHs do not need to be fed throughout the day (or night) - that is one of their prime virtues. Depending on the weather, a rocket mass heater sized for the space will only need to be fed for an hour or two once or twice a day. In really cold weather, it will need to be fed longer in a burn session, but not more sessions. It keeps heating all day and all night without a fire burning while you are away or asleep.

[@HardcoreSustainable]

@@gjh42 I have yet to see one that works like you are saying, but I'd like to. I know that the idea is to heat up the thermal mass and then radiate it to the space for a long time after. I don't know why Mark would say that about needing to be home all day. If you aren't there you might not need it to be warm, but if you don't keep it warm it will take a while to get the thermal mass heated again.

[@gjh42]

The point of thermal mass is that it doesn't transmit heat fast, and once heated, it takes many hours to cool down. The exterior surface may not reach its peak temperature until several hours after the fire goes out. Another fire 12 hours later will maintain the exterior surface temperature fairly steady. Mine works this way. I would love to show it to you.

[@gjh42]

A 6" J-tube system is only adequate for a small house or a large room, in a colder climate. For a location where the temperature can get below zero F, you want an 8" J-tube system (or a 6" batch box) to heat an ordinary house. A 6" J-tube will have maybe half the heating capacity per hour of an 8", so you would have to burn considerably longer to get the same amount of heat.

[@estut]

Hm. Tiled stoves are better ...