In this episode Paul and Jocelyn continue their talk about how they heated their house with 0.6 cord of wood. They talk about the things that contributed to them using more wood than would have otherwise been necessary: e.g. no curtains on the windows and the windows not being able to close properly because of ice on the sills. They also talk about things they do to reduce the amount of wood needed - e.g. using incandescentlight bulbs, dog bed warmers not using vents in the house and cooking home made food.
They discuss why rocket mass heaters are not more known in the world and why people who have no experience with RMHs are so quick to dismiss their efficiency.
They refer to the YouTube series about common misconceptions about RMHs:
Ash Jackson is The Scrollbard
You mention wanting to reduce the exhaust duct to 4" to reduce the exposure to the cold, and the question is whether that will adversely affect performance. I wonder if you could test this by either adding a reducer to the end of your current exhaust, without changing out any pipes. Like just cutting a piece of wood that has a 4" hole it, and attach it to the end of the pipe outside the house, and then try using it that way for a while? Since it's temporary I don't think you would have to worry about it rotting due to the moisture. I would position the hole to line up with the bottom of the existing pipe, so any condensation drips outside, rather than back down the pipe.
I'm not quite a lumberjack, but that's OK, I sleep all night and I dream all day; I'll coppice trees, I'll grow my food, and compost poo and pee! With a well and off-grid solar, it's a permies life for me! https://www.youtube.com/watch?v=FshU58nI0Ts
I listened to your podcast, and I feel like the reason most people don't really know about rocket mass heaters is that most people (at least in the US and Canada) seem to operate only from a standard set of finite actions from the set I would classify as "normal actions." (I have spent many a year attempting to determine this set so I can figure out why everybody thinks that I am so strange! Ha ha!) That is, they do not seem to seek out novel solutions to problems. if they can find it in the catalogue that happens to arrive in the mail, or they can buy it off the shelf at Home Depot, or it's whatever the furnace installer says that everybody is getting these days when he tells them their old one broke, I think that is mostly what they get. A small percentage of normal people will instead be searching for whatever looks coolest in the rich-rich high fashion houses magazines, and don't care at all about the price but it has to look snazzy for the dinner party. Despite the high cost of heating, I think most normal people are fine with that because it is within the scope of normal actions to have a high cost of heating in the winter. Having a low cost of heating in the winter might actually make them feel uncomfortable! Perhaps it is a safety in numbers feeling.
You were asking why people know about the Tesla but not as much rocket mass heaters- I do think they would not skip a marketing campaign. But if you had to build the Tesla yourself, I don't think most people would know about it!
So it seems to me that if my evaluation is correct, then what is needed is investment money to create an off-the-shelf (at least as much as your average wood stove is off the shelf) version of a rocket mass heater which has passed all safety tests / laws Etc. Which seems to point to the need for fundraising, angel investors, all of which is as mysterious to me as the fashion clothing industry. (You said there was a core which a person can purchase, but it's still not plug and play, right? Or am I misunderstanding that item?)
My only other thought is that perhaps just call it a normal name, like a RocketMass brand wood stove, so they aren't overly alarmed by its awesomeness? I feel like the average normal person would like it, once they got used to the idea!
"Be a treasure to the poor, an admonisher to the rich, an answerer to the cry of the needy... Be as a lamp unto them that walk in darkness..." - Baha'u'llah, Epistle to the Son of the Wolf
I just learned what podcasts are! So exciting! Now I have a lot of catching up to do...
Two things, one I believe the reason it's not mainstream is because we as Americans are severely lacking the ability of constructing things by hand any more. I teach automotive mechanics for a local community college and it's amazing that some of these kids don't know what a screwdriver or a wrench is. I basically have to start from nothing with these kids. When I first took automotive classes in high school I had already rebuilt an engine from reading a book and my kind father letting me destroy his garage for several months while I taught myself. It took two attempts. The first engine did not work. After more research and perseverance the second engine did.
All of my projects usually fail 1-3 times before succeeding.
I don't feel like people today are willing to accept failure is a part of it and we must adapt and overcome. If they built a rocket stove that didn't work correctly, most would give up.
I often think about ww2 and how we as a nation came together and retooled factories and everyone went to work to support the war effort. I feel today, there is not enough skilled labor to do the same. We have the factories but do you really think we could as a country support a war effort with our current labor force....I doubt it.
The second thing I wanted to mention, you talked in the podcast about capping the system but people would forget to take the cap off. I installed a propane instant hot water heater in my house, inside the 4 inch flue I had to install what's called a back draft device. It's a flap that allows flue gases out but does not allow cold air back in when not running to prevent the heat exchanger full of water from freezing. Perhaps you could use one of these automatic devices for your heater.
If you did reduce the exhaust to 4", I would do it after the U-turn dip so as not to add more drag from the small elbows. I don't think a 4" dip would retain any more heat than an 8" dip - it's the dip that does that, not the restriction. And the smoother the transition to 4", the better. Changes in size add drag even without changes in direction. (I used to size ductwork for HVAC systems in a past engineering job.)
This might seem a bit silly, but has anyone considered starting a Rocket Mass Heater Association? I've been doing some online searches (partially out of curiosity, and partially because I might be having to choose a form of heat for a house soon). So, bear with me.
Googling Rocket Mass Heater gets me a few superficial articles, links to permies (which, by the way, totally enforces the "RMH for tinkerers" image), and an RMH company that is still trying to raise funds, doesn't have a product yet. Several of the articles mention using insanely small amounts of wood, 10% of what is used in a 87% efficient woodstove. As a reasonably intelligent person, if I were just looking for heating options, I'd think "bullshit" and move on to something that sounded realistic. (Please note, I'm not disputing the claims. I'm simply saying that we sift through internet information by comparing to what we already know. If something sounds way out there and we don't have the time to investigate, we go with what we know.) If I do try to investigate, I find that there is nobody with credentials backing up the claims - nothing from the EPA, or any official sounding organization. Just a few individuals making a lot of arguments that are hard for me to evaluate because I've never actually seen a rocket mass heater, and don't really understand regular wood stoves that well.
If I do become convinced to try it and am not a DIY tinkerer, I google "RMH installation in my area" and get - nothing. I might find Ernie and Erica's website (surprisingly low on the list of hits), and find that I can pay $300 for an initial consultation, buy plans, then find as many as four different types of licensed and bonded builders to build the thing - and let's not forget figuring out the local codes and home insurance issues.
If I google Masonry heaters (which seem closer to RMH than anything else), I get the Masonry Heater Association, with a snazzy website, professional looking photos, reasonable sounding claims, articles outlining the code requirements, and - this is important - a list of contractors and company-members, sorted by country and state. If I choose to go with a masonry heater and am not a DIY tinkerer, I now have a clear way forward - I read the website, contact a local builder, and have them guide me through the code and inspection process in my area.
Perhaps an RMH association - with a website, and member-contractors around the country - would give the technology the initial gut-check credibility it needs to get people interested enough to investigate further?