Rocket mass heater review after two years of use. The truth about mass heaters!
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- čas přidán 20. 08. 2024
- In this video we review our rocket mass heater after two winters of using it to heat our home.
The book (you definitely need this to build a heater)
The Rocket Mass Heater Builder's Guide Complete Step-by-Step Construction, Maintenance and Troubleshooting
Erica Wisner, Ernie Wisner
ISBN 9780865718234
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Physical DVDs: permies.com/wi...
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Commercially available rocket heaters.
Europe: rocketheaterga...
US: rocketheater.com/
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Speaking of being good with heat, on of our previous cats learned to flick the kettle on so she could keep herself warm overnight. I always refill for the next person but my mum doesn't so we had 2 kettles burn themselves up because of that
High tech cats! I love it.
Super interesting points about how the damper functions for you in a high-wind environment, I wouldn't have thought about the gases being pulled through the bench too quickly. Thank you!
Thanks!
this is great to hear. there are so many who've built a rmh and put up reviews when first built, but rare to see the long term reviews. just need you to pop down to Stockport and give me a hand building mine! stay toasty. oh, cover for the burn chamber - look for a small anti splatter cover for a frying pan
That would work!
Very inspirational! I've been looking for a series of videos to get me started on a RMH for our home. Your series was just the ticket. Thanks for an interesting, inspirational and entertaining video.
Thanks!
I was so glad when I found your channel a few months ago …. to find folks who think like me!
Wanted to also let you know that Paul Wheaton spoke favourably about you in his livestream last night.
Thanks for sharing your wisdom and knowledge - much appreciated.
Ah that's fantastic, thanks for telling me! I'll take a look.... Do you have a link?
@@CairnOfDunnCroftPermaculture This guy: czcams.com/video/s7SyEqicLnk/video.html&pp=ygUOcGF1bCB3aGVhdG9uICA%3D
czcams.com/video/WfUHynKuCNE/video.html@@CairnOfDunnCroftPermaculture
I've long been fascinated by different methods of burning fuel wood. The advancements in wood burning in the last 30 years or so have been incredible, both in the exploitation of "rocket" designs that burn fast, hot and clean, but also in traditional wood stoves, that now gracefully and steadily perform most of the combustion of the wood "above" the wood in form of secondary combustion and catalytic combustion, which, combined, allow for fairly extended burn cycles and subsequent heat life from some of the heavier stoves.
We do about 75% of our heating with a relatively large modern wood stove mostly just because I enjoy processing wood and making fires. I estimate we burn on average about 2 cubic foot of ponderosa per day through the "heating season." That's around 330K BTU per day "burned" and I estimate about 250K BTU's stay in the house. The remaining BTU's are used to safely discharge the non-condensed wood gases out of the wood heating system so that the chimney and stove pipe stay pretty clean and safe over time. Since we burn very sooty pine here I clean the chimney, stove pipe, and cats out 2-3 times per season. The system frequently produces that ideal "just steam" exhaust that condenses into the cold air as a white cloud inches away from the chimney cap. I call that a win for balancing efficiency with ease of daily use and maintenance considerations.
I see a lot of these video's on rocket stoves but often feel they are presented without a clear picture of how much fuel is being burned daily when one of these is used as a primary heat source. I would expect these these can produce 95% or better efficiency much like a modern condensing natural gas furnace, but at what cost in terms of cleanout? I sometimes wonder if the reason these appear to produce such clean looking exhaust is that a lot of the particulates are being left behind in the system and "drained down" with the condensate. You mentioned having some issues with green wood, but even dry wood produces a significant amount of water vapor in the combustion process. I wonder how the "long term" on these works out with regards to deposits in the system. I love how your design has lots of cleanouts! Very wise!!!
Good to see you both in the video!
So delighted you gave a review after you have lived with it!
Thanks!
@@CairnOfDunnCroftPermaculture in your next video about this in a few years make sure to mention how cleanly of a burn this design it. It burns 90% of the wood gases.
Something most don’t really understand.
great review. i didnt realise that you're in caithness. i'm renovating an old place near Halkirk and planting willow and planning on putting a couple of rocket mass heaters in the house too as i want a rocket mass bed in my bedroom and then a rocket mass sofa in the living room as my house is very long. I was thinking exactly the same regarding the baffle in the chimney pipe because the wind howls where i am, as i can see the flow country on a clear day and see orkney the other direction and the wind just rips through here at the top of the river thurso valley. Storm babet last week gave me 63mph gusts for about 48 hours. When i rebuild my big outbuilding and add an upstairs floor i'm planning on more rocket mass heaters and specifically one which is a staircase but i'll need to look if that's possible. If it isnt with the rocket mass, then i have seen staircases made with masonry heaters, so i'll just build one of those as then it serves 2 purposes - heating and stairs which is perfect. until the willow grows, ive got loads of wood offcuts as i have a sawmill as i buy logs and cut my own wood to do the renovations on the house. Currently i'm in a static caravan with LPG central heating and its killing me as theyve put my LPG up by 62%, I'm hoping to get roofed next summer and may even get just one roof done over winter to have a dry work space as i got nothing done this summer due to all the rain stopping me using power tools outside all the time and stoppingand starting and taking tools out then in then out and in until you just give up for the day.
We're up on the ridge near Watten, so similar wind.
That sounds like an amazing project!
Wonderful review!! Thank you for taking the time to do this.
Thank you!
Thanks. Stay warm and toasty!
Thanks, you too!
@@CairnOfDunnCroftPermaculture after sleeping on it, I have a few questions :D
1. how cold does it get during the winter in your area?
For example, in my coastal, not so urban area in Croatia we barely ever go down to minus single digits °C and the coldest it gets is right before morning. Currently we are going through second spring this year.
We do get strong cold winds (half a dozen times per year) from the continent which brings the "real feel" down a bit, but that only last a few days at a time.
2. how many hours per day do you keep the rocket running during the coldest part of the year?
3. how often do you need to load wood into the stove?
I've heard some people claiming how rocket heaters are great, but they require constant supervision. Which to me sounds a bit strange.
For example, I have seen people running rocket stoves without the mass part and they seem to be burning through a lot of wood, which goes hand in hand with a raging fire they get going.
To me it seems the pivotal function of rocket mass heaters is to accommodate for a slow, high temperature, complete burn. No soot, low temperature exhaust, a large warm mass that keeps radiating heat for hours, maximum efficiency.
4. (and final question :)) in reference to relatively low temperature exhaust fumes, I have heard from some people that basically the relatively high exhaust temperature is require to obtain an optimal draft. Something with the temperature difference, the claim was that the chimney won't be able to draw as much air if the fumes were insufficiently hot.
Have you come across anything of the kind? You are, of course, in a very windy area so maybe not that applicable to your situation.
BTW, I have started reading the book you have brought forward, thanks for the recommendation.
@@mkeyx82 1. The coldest recorded temp here is -10c, but it's consistently windy so that also has an effect of course.
In winter we usually run it for an hour or so, unless there's a strong wind from the north. Then we run it longer. In severe storms we've occasionally run it all day, but then it doesn't need to be lit the next day because the mass is so warm.
3. It needs less attention than the old open fire did. It needs fuel adding every 30 mins or so, depending on whether it's hardwood or softwood, and the thickness of the fuel.
4. There is a rough formula for max flue length in the book. If you stay within that, it'll draw well.
@@CairnOfDunnCroftPermaculture One hour per day? Well, in that case loading it a few times, every 30 minutes really is not a big deal. Thanks for the response, this heater looks better and better the more you learn about it.
15C? The only scenario where that would not be uncomfortable is if you have a super-warm summer and desperately want to cool down...
Sweating in 24C on the other hand?
I don't it's allowed to DIY a rocket mass heater (or self-made fireplace) in my country - would need to hire a professional I believe. First winter in our new (old) house coming up now - we do have a modern oven in our living room though (but the very first generation of them) so will be interesting to see how we fare (in the bedroom we have an old oven - that one doesn't seem to be very efficient...)
In my era we are dog trained to such extent that people ask permission for everything. But unless you have some nosy neighbors, I don't know that anyone will ever get to see your stove, unless you want them to. If there are no "mandatory" chimney inspections, I think you should be good.
@@mkeyx82Not only inspection, but chimney sweeping every year (ish - depends on how fast soot builds up).
Will have to double-check the rules (my memory might be flawed, and it has been some years since I checked). Wouldn't want to fight the insurance company if my house burned down... Not sure how much it would cost to have a professional build it (or maybe it would suffice that a professional checked a diy-project), but first I will have to wait and see if we need to do adjustments or not :)
@@saethmanyes, insurance games are a never ending stream of delights. A lot of hoops to jump through.
I wonder if you could get a professional to install a wood stove and then do a mass heater style creation around it, AFTER the insurance people have seen the stove and approved it. You wouldn’t get the savings, but you could makeshift the thermal mass heat conservation.
@@misstweetypie1Might be allowed to get a professional to install the thermal battery part of it?
Thanks for the review of your rocket mas heater. That is bizarre that a crow went down your chimney!
Not the first, either!
trust snoop to show you a potential fire risk, with that tail down the burn chamber, lol! cats! i also like that idea for a cook's spattershield
what's your average winter temp now, comparing to that bracing 15°C pre install?
informative and inspirational, thank you🙏👍
15 is now our minimum really. We burn the heater when it drops that cold, rather than it being the maximum possible temperature. And don't forget that's the air temperature, it feels much warmer because the radiant heat isn't measured by thermometer.
@@CairnOfDunnCroftPermaculture measured by dress, then: do you still rug up or is it t's or light sweaters territory in deep winter?
in my housing association property there is a heat pump with rads, & solar panels on the roof. indoor thermo is set at 16.5°C, and throughout winter the house feels comfy. it is also well insulated, with that foam padding they wrap exterior walls of houses in these days, with dg windows & doors. i am very grateful.
and, i would rather have a rmh setup. (no chance, btw, in ha property). i prefer the LIFE of daily interaction with the elements that keep body warm and spirit content.
here, one flicks a switch once, sets the thermostat, and ignores the entire setup for the next 5-6 MONTHS, the heat pump staying on 24/7 & running when indoor temp drops below thermo setting.
the disconnect is extreme.
does yours do for that room only with icy rooms elsewhere?
@@-abheda typically I'll wear a light fleece until the heater is lit, afterwards it's just too warm. currently the only room that can be a little cold is one bedroom. I could build a small rocket heater for the room, but the long term plan is to wrap that side of the house with greenhouse, so the solar gain should make a big enough difference.
@@CairnOfDunnCroftPermaculture wow. erm. do you mean your one rmh basically heats your house?? or have you other heating solutions elsewhere?
@@-abheda The RMH heats the whole house. It's built in the lounge/kitchen/diner, so heats that space well. The back side of the heater has a cutaway in the wall to heat the bathroom. All that's left are the bedrooms, and we just open the doors once the main living area is getting a little too warm.
This is brilliant.
I am intrigued, instead of a bench could the flue pipe system be used under a floor?
Absolutely yes, it's been done. Another option would be a wall in a central location so it heats several rooms.
@@CairnOfDunnCroftPermaculture Brilliant.
We are planning on moving to Scotland next year (Ballindalloch, Tomintoul, Buckie type area) which is lower than where you are, do you know if these heaters are legal/accepted in those places?
I put our own log burner in a few years ago, and it is great, however I would much prefer something like what you have done.
@@dazzc4946 as far as I know, there's no legal issue with building them in Scotland.
Damper? I live in South Dakota, might as well be the channel all the wind gets to America through from Canada. A flue damper 19:05 is definitely necessary.
Fabulous!
Thanks!
Is the ash that's created a bio charr byproduct 🤔. Where does the bio charr come from. Thanks for making this video 🤗
The ash is from just burning wood very efficiently. When the fire is low, and I'm letting it go out, I pick out the last coals with tongs and quench them in a pot of water. That's the biochar.
Great review I myself made a thermal mass roket heater and we love it ! I'd like to know what you think of it if you would take a look ? My only regret with ours is we don't have the availability where our fire is to put a cob bench so it's only the roket and sand battery that we use but it does an amazing job . We are also in a town so no chance for us so be sustainable with out own branches however I have a plan for that with asking for branches from local tree surgeons that way they don't have to chip as much ! Hmm cunning plan I have right ? Nice to see a UK stove too no offence made there 😅
Thanks!
Any thoughts on cob/haybail retrofitting the exterior of the old building? Excellent stuff anyways friend's
Thanks! I'd love to cob the inside of the old barn, and wrap the whole building with lean to greenhouses.
Very good to hear what you have learned , thank you for your video.
Thanks!
I remember watching your original rmh video when it first came out so great to hear its still going strong!
One question - where you mentioned newer models use a stratification chamber. Im assuming this is the "bell method"? If so do you think theyre as good (or better) than the pipe method you've used?
I'd certainly have to give it some serious thought on the next heater build. I can see that the potential for efficiency could be a little higher with a bell/stratification chamber model, but I do love the simplicity of the flue. I think for an indoor model I'd still favour the flue, keeping it safely sealed seems easier.
This is the only channel I let the ads run. Hope you make a penny or two.
Very good video, thanks for sharing! Any reason you did not go for the stratification mass heater so no pipe rather than the pipe version? Thanks.
This first heater I wanted to be by the book. I'll be a little more creative with the next ones probably.
Thanks for these videos. I am putting together a RMH project and I have a question. You have the bench made with cob and stones. What element heats up faster, the stones or the cob. Conversely, which cools down first...are the stones still warm after the cob has cooled?
I've not run any specific tests on that, but the whole mass seems to heat and cool at the same rate.
Would you still go with this design if you could redo it or would you go with a batch heater, also would you incorporate a design which gets hot water from the mass heater too
I'd still stick with the same design. I do have a plan for hot water, but it'll run from the stove in the kitchen so I can still get hot water in summer when I don't run the heater.
Aren't you the one who had to redo the floor supports, fill in the fireplace that had a heating tube for water? I literally watched that video last night.
That's me!
Here's the problem I had with my homemade refractory out of regular morter, and perlite :
czcams.com/video/wFLrhgPxoXk/video.htmlsi=Q8iPbisH-4vbMHEN
Hi mate weherr are ye from, Alba? Sorry Scotland?
Cairn of Dunn, sounds as a place in Scotland
I been in dunfermline, not to far the north crossing the firth of forth, Fife
I'm up in Caithness, between Wick and Thurso.
Great job. What size is your house? My house is 450 square meters. Would it work in my house?
We don't tend to measure houses that way in the UK so I'm not sure of the size. But this is a 6 inch heater. For a bigger house (and my house is pretty small) I'd go with an 8 inch flue. It produces significantly more heat.
So if I want electricity to still be working in 4 centuries (not really something one should want, but...), I should invest in building a 30 brake horsepower steam engine with a rocket boiler, and building a self-exciting dynamo?
Here, I'm going to go with simple wind generators. Steam has a huge capacity for accidents, compared with wind power.
@@CairnOfDunnCroftPermaculture although that has to be weighed against the fact that capacity for accidents make for increased video views....
So how much wood do you end up using a season? One, two, three cords?
We don't measure wood by the cord here, so it's impossible to say.
Paul Wheaton says he uses 0.6 cords/year in Montana
Bu where is this legal, ul all that jazz. They would kick me out of town, bank would no loan, insurance would cancel
Where I live it's legal.
Even in the US, most states now permit mass heaters if they're built to code.