11 ms·

Oven Stoves and Heat Walls (2008)

128 points by Rendello 5y ago

apcragg 5y ago
As someone who suffers through winter smog caused by people in my county heating their homes with wood, please please please use a modern efficient heating source instead of this neopasotral quackery.
- woodruffw 5y ago
  Purely out of curiosity (I've never permanently lived somewhere where woodburning stoves were essential for home heating): is this because people are over-burning wood to compensate for the slow warming-up time, or because the stoves themselves are inefficient, or something else?
  - apcragg 5y ago
    The stoves just put off a lot of particulate pollution. Stoves don't completely combust the wood or do so at the wrong temperature which results in much more pollution than burning an equivalent energy amount gas.
    - woodruffw 5y ago
      That certainly makes sense; I've only ever used fireplaces and you can visibly see the particulate those emit. I'm guessing it's outside of the economic envelope in which people are burning wood anyways, but the article makes it sound like combusting at the "right" temperature essentially solves that problem. But I suppose at that point you might as well just burn something cleaner and retain the other advantageous parts of the design.
      - zdragnar 5y ago
        Look up rocket stoves, and rocket mass heaters. Properly built, they effectively produce only co2 and steam, even all carbon monoxide is consumed. Of course, since each rmh is custom built, you need to actually test the exhaust of every one to ensure it works as intended. Mine is pretty swell, albeit a tad annoying to keep going if we leave for a few days and the whole mass cools. With that said, it uses about 1/10th the wood of a new high efficiency wood stove we use in a different building.
        Rendello 5y ago
        For anyone looking to compare masonry heaters with rocket mass heaters, this is a nice introduction: https://www.lowtechmagazine.com/2015/03/radiant-and-conductive-heating-systems.html https://www.lowtechmagazine.com/2015/03/radiant-and-conducti... RMHs are very interesting to me, but unfortunately due to their niche status, they're currently very hard to get insured. (PS. I would love to see a picture of your RMH, is possible!)
        zdragnar 5y ago
        Not mine, but what I based mine on: https://youtu.be/8ptwncPImuo https://youtu.be/8ptwncPImuo Reading that article, I am curious as to why they say that rmh are less efficient than tile stoves. The exhaust temp on mine is around 130-150 degrees F- cooler than a fresh cup of coffee. And yet, I get pretty complete combustion- so all of the heat from the wood is captured inside my house. I recently saw a claim that rmh can produce less CO2 for the same heat than gas furnaces, though that was just someone on the internet, I would definitely want more research to claim that.
  - s0rce 5y ago
    You'd be surprised how common it is, the largest source of air pollution in the winter in the SF bay area is from people burning wood.
    - apcragg 5y ago
      Less that its so common, more that a small percent of people cause all of that pollution. They usually convince themselves they are being environmentally friendly because "I just use the wood I already have from my land!!" And the rest of us suffer their refusal to use a modern heating source.
    - maxerickson 5y ago
      *recreationally
    - dredmorbius 5y ago
      What are the other major sources of air pollution / particulate pollution in the Bay Area? There's no coal consumption to speak of. There's diesel fuel consumption, though that is largely concentrated on transport corridors (I-80, I-580, US-101). Wildfire emissions all but certainly swamp woodstove usage. That said, yes, a small number of poorly-tuned fireplaces can create a large amount of smoke. Where the intent is actual useful heating, and not fireplace-as-decoration, thats' a solvable problem.
      - s0rce 5y ago
        See here for the other sources: https://www.baaqmd.gov/~/media/files/communications-and-outreach/publications/annual-report/baaqmd-guidebook-08-6-4-09.pdf https://www.baaqmd.gov/~/media/files/communications-and-outr... Look on page 7 39% Wood Smoke 12 Cooking 12 Other Mobile Sources 12 Road Dust 7 On-Road Motor Vehicles 6 Combustion: Stationary Sources 5 Industrial/Commercial Processes 3 Construction and Farming Dust 2 Animal Waste 1 Wind-Blown Dust 1 Wildfires Wildfires are basically non-existent in the winter, although the Colorado fire currently doesn't bode well for future California winters.
    - woodruffw 5y ago
      That is indeed very surprising! My understanding is that here in NYC the single largest (non-industrial?) source of air pollution is heating oil. The city banned the two worst heating oils back in 2015, but with a long phase-out period[1]. I would have expected the situation to be the same in most other cities, although SF's weather certainly doesn't justify oil burning the way NYC's does :-) [1]: https://www.ny-engineers.com/blog/how-nyc-is-phasing-out-heavy-heating-oils https://www.ny-engineers.com/blog/how-nyc-is-phasing-out-hea...
  - UI_at_80x24 5y ago
    When I was young (~10 years old), we installed a wood-burning stove in the family-room of our house. My dad had a lot of family and friends who were farmers and were in constant need for tree removal. Our heating costs dropped so significantly that the Gas company called, concerned that we weren't running our Natural Gas fired furnace and that we might need financial assistance. We heated this way for many years after he died. I took up the responsibility of cutting down trees, splitting wood; and keeping the house warm. It is A LOT of work, but worth it if you have access to the trees/woodlots. In the future (if this housing crisis ever ends), I will be adding a Rocket Mass Heater to my home. There is nothing in the world that compares to the feel of a roaring fire on a cold winter. One year the power went out in a very large geographic region that affected a large portion of the population. No electricity meant that no furnaces were running; so we had some elderly neighbors and family move in with us. They could have easily died without our wood-stove running. We even used it to cook on!
    - Rendello 5y ago
      It's very cool that you will be adding a rocket mass heater. They fascinate me endlessly (I've posted about them here before) and are what led me to read about masonry heaters. It's unfortunate that RMHs are so difficult to insure, but I hope that building one is in my future as well.
- hirundo 5y ago
  I live in a very rural area where wood burning for heat makes a lot of sense. We have vastly too much deadwood on the ground and it is a serious fire hazard. There is simply no other economic way to dispose of it than to burn it. Most of it gets burned in vast piles by the county and forest services. From my lot, I divert a few cords per year of that to my woodstove. Either way it is going up in smoke. This way, for an acceptable amount of labor, I heat my house and save about $1,500 a year in propane charges. This is less healthful for me than propane in terms of indoor air pollution. But it is more healthful in terms of exercise and fire prevention. I've accepted that compromise with the help of an air purifier that stays on all winter. Also, when I can get all of my fuel within a few hundred yards of my front door, most of the extraction and transportation costs go away. And there's something else that's very important to me: When I burn propane, I micromanage the thermostat to save money. I wear heavier clothes all winter and end up tolerating being more cold and uncomfortable. With wood fuel being so much more economical, and surfing the edge of comfort less practical, I just keep the woodstove going all day and cool the house at mid day by opening some windows ... getting fresh air that I just don't get when using propane. So the house is mostly warmer all day than with propane, and I'm wearing less and generally more comfortable. It's a pretty easy choice for me. I'd like to keep it up as long as I'm physically able.
  - nerdponx 5y ago
    I wonder if all that excess heat from burning can be captured and stored somehow.
    - 14 5y ago
      I also heat water with my stove. 2 hot water tanks, the first tank is unpowered has cold city water coming into it and is ran through a coil on my wood stove and then cycles back into the tank with a hot water pump. The second tank is powered and draws from the first tank. So cold city water is heated prior to going to my second tank it saves me lots of power each year.
    - genewitch 5y ago
      It can, but it requires building around heated seating in a building. You have an intake, a horizontal inlet pipe, a firebox, and then a 90° into a chimney inside of a dome, made of thick clay. You then use a horizontal outlet to the dome near the floor, with a rectangular cross section a ratio to the interior chimney size, ideally, and you build concrete or clay benches, bedframes, etc around your room, with these rectangular exhausts in the middle. The fire gets going very hot, burns off all of the stuff that comes out of wood, on purpose, to turn into heat, which heats the masonry, which will stay warm for a very long time. The dome also radiates heat for a very long time. The final outlet, out of the house, expels tepid, wet, clean air; contains only CO2 as a byproduct, iirc.
- Rendello 5y ago
  I'm from Northern Ontario, and I agree that wood smoke can be killer, especially below -30°C (-22°F) when the smoke stays near the ground. Oven stoves, according to the article, address this. The section "Complete combustion", is all about this issue: > Wood can be burned without too much air pollution, but then the temperature has to be high enough: 1100 to 1200 degrees Celsius. In that case, 99 percent of the wood is converted to CO2 and water vapour, almost without smoke. A metal wood stove, however, only reaches a temperature of 650 to 700 degrees, with an incomplete wood combustion as a result.
  - wolverine876 5y ago
    > 99 percent of the wood is converted to CO2 and water vapour, almost without smoke CO2 is a critical problem.
    - dredmorbius 5y ago
      In the case of wood, the carbon is accessed from, and ultimately returned to, the active biosphere. It's not fossil fuel that's been sequestered for 100s of millions of years, but was itself captured largely within recent decades. Contrasted with burning coal, oil, or gas, preferred. (Woodfuel may still be burned unsustainably, that's a separate question.) Noted FWIW in TFA: [U]nlike gas and oil, wood is a renewable and CO2-neutral fuel (the CO2 that is produced by the burning of wood was taken out of the atmosphere by the tree during the years before). The problem is that wood stoves are not very efficient, and extremely polluting.
    - ace2358 5y ago
      Whilst it is for burning fossile files, when you’re burning the wood that grew on your property over the past 20 years, the carbon cycle is much shorter. Especially if your property grows it all back, it’s a closed carbon loop.
      - deleted 5y ago
        [deleted]
    - 5y ago
- 14 5y ago
  Modern heating is not nearly as cheap as wood heat, at least around me. The problem is not wood burning as much as it is burning unseasoned wood. There should be strict regulations for firewood sellers ensuring wood is seasoned properly but what happens is every year some guy with a truck cuts a bunch of wood and sells it with very little seasoning. This creates the smoke you are experiencing. I can heat my home for about 2 months for $300 where any other heat would cost significantly more. Not just heat my house but heat it to the point I can walk around in my underwear. I've never been able to afford to do that with any other type of heat. Furthermore I have 2 hot water tanks. The first one is connected to the second and city water enters the first tank and the first tank is not powered. It does run to my fireplace through copper pipe and a copper coil at the stove. So for the price I pay for wood I get excess heat and hot water. No other heat can come close.
twobitshifter 5y ago
These are cool but when talking of alternative heating systems the author misunderstands how hydronic heating (radiators) work and blames metal for being a poor material for holding heat and as heating the air through convection. This is all incorrect, the heat transfer medium is the water which is great at retaining heat, and the heaters heat primarily through radiation (although they do use convection over fins to speed the rate at which they heat the room.) Another form of hydronic heat would be radiant heat in your floor which would be very close to having a oven stove under your feet. I think these are neat and the idea of running a stove for only a short time each day would be great, but the architectural drawbacks should be obvious. The heart of your house is now lost to a massive stone structure. The drawback of taking a long time to heat up shouldn’t be overlooked either. Anyone who has lived in a stone or brick house could tell you that it will stay warm once it’s warm but bringing it up to temperature can take a long while. The same is true of radiant floor heating in a slab. This can make your home difficult to adapt to temperature swings.
- R0b0t1 5y ago
  They have hydronic registers that have very dense copper/aluminum fins and are powered by fans. An extremely small unit can heat a huge area; they are by far the most space efficient system that exists. They are also very fuel efficient. Hydronic heating is usually the best. The problem with floor systems is poor adjustability, usually noticed on cool down times, but the initial heating can also be very slow. With registers you stop flowing the water and turn off the fan. Or do the reverse and make the air hot immediately.
- hasmanean 5y ago
  Yes, even a metal stove can be efficient…it does not have to be made of stone. The efficiency increase of a proper designed wood stove over a fireplace is due to two factors 1. Metal wood stoves slow the combustion rate down by blocking incoming air. So they can burn logs over several hours rather than all at once. Obviously the stove must be airtight. Russian wood stoves just use a mass of masonry and have lots of internal baffles to extract the most heat. They burn a large fire at a high temperature to have increased efficiency and extract the most heat into the stone. 2. Both types of stove use high temperatures and preheated secondary air to achieve complete combustion. Open fireplaces let 50% of the energy in the wood escape as unburned gases.
Maursault 5y ago
I don't know how the Kimberly [1] fits into the essay. It has two combustion cycles to burn clean and more efficiently. It's relatively expensive compared to most wood stoves. Originally designed for heating a boat, thus compact. [1] https://www.unforgettablefirellc.com/kimberly-wood-stove/ https://www.unforgettablefirellc.com/kimberly-wood-stove/
- carapace 5y ago
  That seems awesome!
minerva23 5y ago
Article: > The energetic output of an oven stove is 80 to 90 percent, compared to 40 to 50 percent for metal stoves or central heating appliances Energy.gov > Old furnaces: 56% to 70% > Mid efficiency furnaces: 80% to 83% > High efficiency furnaces: 90% to 98.5% https://www.energy.gov/energysaver/furnaces-and-boilers https://www.energy.gov/energysaver/furnaces-and-boilers EDIT: We can cut the article some slack as ducting (as typically done) does account for losses which are highly variable.
- phgn 5y ago
  Well, what does "energetic output" mean? If I understand the core point of the article correctly, radiant heat only heats the surface of objects not the air, so it will require less heat for the same effect. I don't how to put a number on this. I think the energy.gov article you mentioned primarily talks about heat leaking outside: > An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere.
- stonkdonk 5y ago
  this article lost me when I saw those numbers. It also treats heat like some kind of magic and not based on thermodynamics. heat is heat, no matter how quickly or slowly it spreads. A big thermal mass will hold heat, but will also take longer to heat in the first place. You're spending the same number of BTUs in the long run.
stormbrew 5y ago
I think heat pumps are far more likely to be a 'savior' in terms of energy efficiency and climate issues than going back to burning wood en masse, which the end of this article handwaves away even though it seems pretty obvious that it isn't really sustainable.
- duxup 5y ago
  And heat pumps can be fit into existing systems.
  - hasmanean 5y ago
    Yeah but this “system” has advantages heat pumps don’t have. Such as the lack of a convective air circulation system.
    - duxup 5y ago
      So… then you can’t use it to heat other rooms. That’s not an advantage.
      - hasmanean 5y ago
        Yes…it’s not a solution suitable for western style houses. But maybe if you designed your entire house around the large central fireplace…it could work. I imagine that’s what they do in Siberia.
- ulrikrasmussen 5y ago
  Manually operated wood furnaces are also terrible with regards to particle emissions. The article acknowledges that and claims that oven stoves do not have this problem because they can reach higher temperatures. But that ignores the fact that there is a time period until the fire has reached the right temperature during which the particle emissions are very high (particle emissions from wood furnaces are scary high and dwarf emissions from cars). If the whole neighborhood is heated by these things, then you have several hours of the day with smoke and particles, even if everyone operates their ovens correctly so they reach the correct temperatures for a clean burn. Furthermore, heat pumps are just so much more efficient, as they actually move several times the amount of energy as heat as they consume as electricity. Combined with floor heating - which gives a much larger surface area for heat dissipation than these oven stoves can ever give you - you can further lower the temperature of the water, raising efficiency even more. Floor heating is also way more comfortable as it gives an even distribution of heat throughout the house, and you don't get cold feet.
14 5y ago
What I wondered about these brick stoves is how do they clean them properly? Surely they need to be cleaned of build up periodically as a woodstove needs to be done annually to prevent chimney fires.
- Tcepsa 5y ago
  I suspect, though I have no documentation, that they are generally built with "cleanout" access points along the exhaust path (possibly in the form of "these are the stones to chisel out if the thing needs cleaning; be sure to mortar them back into place when you are done!")
- AngryData 5y ago
  If they burn hot enough there should be almost no volatiles left. Most chimney buildup is from fires/chimney being too cold, improperly seasoned wood, or burning the wrong types of wood/not mixing those poor burning woods with other woods. Ash buildup could still be a problem, but would take years to build up enough to be a problem, although it likely would still need to be cleaned out at some point, although a vacuum with a proper filter could be an option or have access points built in for that eventuality.
  - 14 5y ago
    I’ve burnt for years and absolutely build ultra hot fires occasionally to get ride of creosote build up but eventually like you say will get ash build up which can burn or eventually just plug the pipe. You would need access points to use a vacuum because the article showed these things zig zag back and forth to make the heat travel around the bricks. Maybe it just takes years and years since the article claims you only need to burn for a couple hours a day where my wood stove burns all day.
dukeofdoom 5y ago
These work very well. That's why I'm a little surprised none of the youtube build your own cottage videos people every try putting one of these in, and always do the metal stove. WhichI don't believe will keep you warm all night, without having to get up and add more wood. I've experienced radiant floor heating powered by a wood stove, on my trip to Europe, it was very nice. Not sure how it worked.
blaydator 5y ago
In France, https://www.uzume.fr/ https://www.uzume.fr/ is releasing open source plans for self building « batchblock » a mix between a rocket stove and a mass heater.
jkaljundi 5y ago
Strange sentence there: "In a room that is heated by an oven stove, a thermometer can hardly measure anything." Saying that as someone heating my house twice per day by wood brick oven and having multiple thermometers to measure the ambient air in the rooms warming.
jkaljundi 5y ago
Something to keep in mind though: https://www.theguardian.com/environment/2021/dec/17/wood-burners-urban-air-pollution-cancer-risk-study https://www.theguardian.com/environment/2021/dec/17/wood-bur... "Wood burning stoves in urban areas are responsible for almost half of people’s exposure to cancer-causing chemicals found in air pollution particles, new research has shown."
- pygy_ 5y ago
  This is less of a concern with modern batch-rocket stoves that also burn fine particles, once hot, after a few minutes, they burn without smoke.
  - trompetenaccoun 5y ago
    Unless the wood is moist. Or the logs are too large. Or the wood is of the wrong kind or of bad quality. Or the stove is used incorrectly (ID10T error).
    - switch007 5y ago
      Exactly. The average user has to be very cautious. I wonder how cautious they are having paid good money for a fully compliant stove install and then think their job is over.
    - euroderf 5y ago
      Are these user-originated problems detectable using the right combination of sensors ?
      - trompetenaccoun 5y ago
        If they paid attention they'd notice it smokes. There's usually a small window in the oven for that purpose, our eyes and noses a good enough sensors for that.
ajuc 5y ago
Old rural houses where I'm from were basically a huge kitchen/dinning room build around this kind of a stove + the rest of the house. The oven heats water in pipes going through the masonry and they heat the rest of the house through radiators. And then you also use that water for bathing. So you cook in the evening so that you have hot water for bathing before going to sleep and the house is warm through the night. It also has warm shelves near the ceiling used for drying clothes/shoes/fruits/mushrooms. Very efficient, but it means the whole house is build around it.
- kpmcc 5y ago
  This sounds awesome.
maweki 5y ago
Just as a tiny nitpick: the German word "Kachelofen" does not translate to "oven stove", but to "tile oven" - a term mentioned at the beginning of the same paragraph.
pygy_ 5y ago
There are modern takes on this idea, with highly efficient (85%) burning cores that also burn the fine particles traditionally present in wood fire smoke, resulting in a smoke-less combustion. Plugging https://www.uzume.fr https://www.uzume.fr (site in French) an engineer and indie stove maker that makes neat products starting at €4000 for a stove kit that you build yourself.
phgn 5y ago
> Today’s energy crisis is not the first in human history. The article is from 2008, I wonder what the author refers to here. Possibly using more environmentally sustainable energy sources? Or using less energy in general?
pelasaco 5y ago
That brings me the good memories from the east Germany times, when we all spent our nights around such heaters. They were great, but I assume that would be impossible to have such things today when people want to dictate how we all should produce CO2.
tiku 5y ago
I'm still waiting on the oven/fireplace with a water pipe for exhaust fumes. We could filter it through water like a bong right? In that case you could burn newspapers, advertisment material all in your home.
tomohawk 5y ago
The rocket mass heater is the modern replacement for this. https://www.youtube.com/watch?v=fwCz8Ris79g https://www.youtube.com/watch?v=fwCz8Ris79g Uses about 1/10th the fuel, and fuel can be wood unusable in other stoves. Very little exhaust / smoke. Super efficient.
t0bia_s 5y ago
I live in center of historical city in middle of Europe. All houses are from 15th to 19th century and most od them has chimneys. In our house there are two oven stoves and we use it during winter. We are able to keep 21°C in entire house even during -10°C outside. With rising prices of gas, it is incredibly handy and saves money. House has old wood windows, not ideal for keep constant temperature inside and yet, it works great.

128 points by Rendello 5y ago

As someone who suffers through winter smog caused by people in my county heating their homes with wood, please please please use a modern efficient heating source instead of this neopasotral quackery.

woodruffw 5y ago
Purely out of curiosity (I've never permanently lived somewhere where woodburning stoves were essential for home heating): is this because people are over-burning wood to compensate for the slow warming-up time, or because the stoves themselves are inefficient, or something else?
- apcragg 5y ago
  The stoves just put off a lot of particulate pollution. Stoves don't completely combust the wood or do so at the wrong temperature which results in much more pollution than burning an equivalent energy amount gas.
  - woodruffw 5y ago
    That certainly makes sense; I've only ever used fireplaces and you can visibly see the particulate those emit. I'm guessing it's outside of the economic envelope in which people are burning wood anyways, but the article makes it sound like combusting at the "right" temperature essentially solves that problem. But I suppose at that point you might as well just burn something cleaner and retain the other advantageous parts of the design.
    - zdragnar 5y ago
      Look up rocket stoves, and rocket mass heaters. Properly built, they effectively produce only co2 and steam, even all carbon monoxide is consumed. Of course, since each rmh is custom built, you need to actually test the exhaust of every one to ensure it works as intended. Mine is pretty swell, albeit a tad annoying to keep going if we leave for a few days and the whole mass cools. With that said, it uses about 1/10th the wood of a new high efficiency wood stove we use in a different building.
      - Rendello 5y ago
        For anyone looking to compare masonry heaters with rocket mass heaters, this is a nice introduction: https://www.lowtechmagazine.com/2015/03/radiant-and-conductive-heating-systems.html https://www.lowtechmagazine.com/2015/03/radiant-and-conducti... RMHs are very interesting to me, but unfortunately due to their niche status, they're currently very hard to get insured. (PS. I would love to see a picture of your RMH, is possible!)
        zdragnar 5y ago
        Not mine, but what I based mine on: https://youtu.be/8ptwncPImuo https://youtu.be/8ptwncPImuo Reading that article, I am curious as to why they say that rmh are less efficient than tile stoves. The exhaust temp on mine is around 130-150 degrees F- cooler than a fresh cup of coffee. And yet, I get pretty complete combustion- so all of the heat from the wood is captured inside my house. I recently saw a claim that rmh can produce less CO2 for the same heat than gas furnaces, though that was just someone on the internet, I would definitely want more research to claim that.
- s0rce 5y ago
  You'd be surprised how common it is, the largest source of air pollution in the winter in the SF bay area is from people burning wood.
  - apcragg 5y ago
    Less that its so common, more that a small percent of people cause all of that pollution. They usually convince themselves they are being environmentally friendly because "I just use the wood I already have from my land!!" And the rest of us suffer their refusal to use a modern heating source.
  - maxerickson 5y ago
    *recreationally
  - dredmorbius 5y ago
    What are the other major sources of air pollution / particulate pollution in the Bay Area? There's no coal consumption to speak of. There's diesel fuel consumption, though that is largely concentrated on transport corridors (I-80, I-580, US-101). Wildfire emissions all but certainly swamp woodstove usage. That said, yes, a small number of poorly-tuned fireplaces can create a large amount of smoke. Where the intent is actual useful heating, and not fireplace-as-decoration, thats' a solvable problem.
    - s0rce 5y ago
      See here for the other sources: https://www.baaqmd.gov/~/media/files/communications-and-outreach/publications/annual-report/baaqmd-guidebook-08-6-4-09.pdf https://www.baaqmd.gov/~/media/files/communications-and-outr... Look on page 7 39% Wood Smoke 12 Cooking 12 Other Mobile Sources 12 Road Dust 7 On-Road Motor Vehicles 6 Combustion: Stationary Sources 5 Industrial/Commercial Processes 3 Construction and Farming Dust 2 Animal Waste 1 Wind-Blown Dust 1 Wildfires Wildfires are basically non-existent in the winter, although the Colorado fire currently doesn't bode well for future California winters.
  - woodruffw 5y ago
    That is indeed very surprising! My understanding is that here in NYC the single largest (non-industrial?) source of air pollution is heating oil. The city banned the two worst heating oils back in 2015, but with a long phase-out period[1]. I would have expected the situation to be the same in most other cities, although SF's weather certainly doesn't justify oil burning the way NYC's does :-) [1]: https://www.ny-engineers.com/blog/how-nyc-is-phasing-out-heavy-heating-oils https://www.ny-engineers.com/blog/how-nyc-is-phasing-out-hea...
- UI_at_80x24 5y ago
  When I was young (~10 years old), we installed a wood-burning stove in the family-room of our house. My dad had a lot of family and friends who were farmers and were in constant need for tree removal. Our heating costs dropped so significantly that the Gas company called, concerned that we weren't running our Natural Gas fired furnace and that we might need financial assistance. We heated this way for many years after he died. I took up the responsibility of cutting down trees, splitting wood; and keeping the house warm. It is A LOT of work, but worth it if you have access to the trees/woodlots. In the future (if this housing crisis ever ends), I will be adding a Rocket Mass Heater to my home. There is nothing in the world that compares to the feel of a roaring fire on a cold winter. One year the power went out in a very large geographic region that affected a large portion of the population. No electricity meant that no furnaces were running; so we had some elderly neighbors and family move in with us. They could have easily died without our wood-stove running. We even used it to cook on!
  - Rendello 5y ago
    It's very cool that you will be adding a rocket mass heater. They fascinate me endlessly (I've posted about them here before) and are what led me to read about masonry heaters. It's unfortunate that RMHs are so difficult to insure, but I hope that building one is in my future as well.
hirundo 5y ago
I live in a very rural area where wood burning for heat makes a lot of sense. We have vastly too much deadwood on the ground and it is a serious fire hazard. There is simply no other economic way to dispose of it than to burn it. Most of it gets burned in vast piles by the county and forest services. From my lot, I divert a few cords per year of that to my woodstove. Either way it is going up in smoke. This way, for an acceptable amount of labor, I heat my house and save about $1,500 a year in propane charges. This is less healthful for me than propane in terms of indoor air pollution. But it is more healthful in terms of exercise and fire prevention. I've accepted that compromise with the help of an air purifier that stays on all winter. Also, when I can get all of my fuel within a few hundred yards of my front door, most of the extraction and transportation costs go away. And there's something else that's very important to me: When I burn propane, I micromanage the thermostat to save money. I wear heavier clothes all winter and end up tolerating being more cold and uncomfortable. With wood fuel being so much more economical, and surfing the edge of comfort less practical, I just keep the woodstove going all day and cool the house at mid day by opening some windows ... getting fresh air that I just don't get when using propane. So the house is mostly warmer all day than with propane, and I'm wearing less and generally more comfortable. It's a pretty easy choice for me. I'd like to keep it up as long as I'm physically able.
- nerdponx 5y ago
  I wonder if all that excess heat from burning can be captured and stored somehow.
  - 14 5y ago
    I also heat water with my stove. 2 hot water tanks, the first tank is unpowered has cold city water coming into it and is ran through a coil on my wood stove and then cycles back into the tank with a hot water pump. The second tank is powered and draws from the first tank. So cold city water is heated prior to going to my second tank it saves me lots of power each year.
  - genewitch 5y ago
    It can, but it requires building around heated seating in a building. You have an intake, a horizontal inlet pipe, a firebox, and then a 90° into a chimney inside of a dome, made of thick clay. You then use a horizontal outlet to the dome near the floor, with a rectangular cross section a ratio to the interior chimney size, ideally, and you build concrete or clay benches, bedframes, etc around your room, with these rectangular exhausts in the middle. The fire gets going very hot, burns off all of the stuff that comes out of wood, on purpose, to turn into heat, which heats the masonry, which will stay warm for a very long time. The dome also radiates heat for a very long time. The final outlet, out of the house, expels tepid, wet, clean air; contains only CO2 as a byproduct, iirc.
Rendello 5y ago
I'm from Northern Ontario, and I agree that wood smoke can be killer, especially below -30°C (-22°F) when the smoke stays near the ground. Oven stoves, according to the article, address this. The section "Complete combustion", is all about this issue: > Wood can be burned without too much air pollution, but then the temperature has to be high enough: 1100 to 1200 degrees Celsius. In that case, 99 percent of the wood is converted to CO2 and water vapour, almost without smoke. A metal wood stove, however, only reaches a temperature of 650 to 700 degrees, with an incomplete wood combustion as a result.
- wolverine876 5y ago
  > 99 percent of the wood is converted to CO2 and water vapour, almost without smoke CO2 is a critical problem.
  - dredmorbius 5y ago
    In the case of wood, the carbon is accessed from, and ultimately returned to, the active biosphere. It's not fossil fuel that's been sequestered for 100s of millions of years, but was itself captured largely within recent decades. Contrasted with burning coal, oil, or gas, preferred. (Woodfuel may still be burned unsustainably, that's a separate question.) Noted FWIW in TFA: [U]nlike gas and oil, wood is a renewable and CO2-neutral fuel (the CO2 that is produced by the burning of wood was taken out of the atmosphere by the tree during the years before). The problem is that wood stoves are not very efficient, and extremely polluting.
  - ace2358 5y ago
    Whilst it is for burning fossile files, when you’re burning the wood that grew on your property over the past 20 years, the carbon cycle is much shorter. Especially if your property grows it all back, it’s a closed carbon loop.
    - deleted 5y ago
      [deleted]
  - 5y ago
14 5y ago
Modern heating is not nearly as cheap as wood heat, at least around me. The problem is not wood burning as much as it is burning unseasoned wood. There should be strict regulations for firewood sellers ensuring wood is seasoned properly but what happens is every year some guy with a truck cuts a bunch of wood and sells it with very little seasoning. This creates the smoke you are experiencing. I can heat my home for about 2 months for $300 where any other heat would cost significantly more. Not just heat my house but heat it to the point I can walk around in my underwear. I've never been able to afford to do that with any other type of heat. Furthermore I have 2 hot water tanks. The first one is connected to the second and city water enters the first tank and the first tank is not powered. It does run to my fireplace through copper pipe and a copper coil at the stove. So for the price I pay for wood I get excess heat and hot water. No other heat can come close.

twobitshifter 5y ago

These are cool but when talking of alternative heating systems the author misunderstands how hydronic heating (radiators) work and blames metal for being a poor material for holding heat and as heating the air through convection. This is all incorrect, the heat transfer medium is the water which is great at retaining heat, and the heaters heat primarily through radiation (although they do use convection over fins to speed the rate at which they heat the room.) Another form of hydronic heat would be radiant heat in your floor which would be very close to having a oven stove under your feet. I think these are neat and the idea of running a stove for only a short time each day would be great, but the architectural drawbacks should be obvious. The heart of your house is now lost to a massive stone structure. The drawback of taking a long time to heat up shouldn’t be overlooked either. Anyone who has lived in a stone or brick house could tell you that it will stay warm once it’s warm but bringing it up to temperature can take a long while. The same is true of radiant floor heating in a slab. This can make your home difficult to adapt to temperature swings.

R0b0t1 5y ago
They have hydronic registers that have very dense copper/aluminum fins and are powered by fans. An extremely small unit can heat a huge area; they are by far the most space efficient system that exists. They are also very fuel efficient. Hydronic heating is usually the best. The problem with floor systems is poor adjustability, usually noticed on cool down times, but the initial heating can also be very slow. With registers you stop flowing the water and turn off the fan. Or do the reverse and make the air hot immediately.
hasmanean 5y ago
Yes, even a metal stove can be efficient…it does not have to be made of stone. The efficiency increase of a proper designed wood stove over a fireplace is due to two factors 1. Metal wood stoves slow the combustion rate down by blocking incoming air. So they can burn logs over several hours rather than all at once. Obviously the stove must be airtight. Russian wood stoves just use a mass of masonry and have lots of internal baffles to extract the most heat. They burn a large fire at a high temperature to have increased efficiency and extract the most heat into the stone. 2. Both types of stove use high temperatures and preheated secondary air to achieve complete combustion. Open fireplaces let 50% of the energy in the wood escape as unburned gases.

Maursault 5y ago

I don't know how the Kimberly [1] fits into the essay. It has two combustion cycles to burn clean and more efficiently. It's relatively expensive compared to most wood stoves. Originally designed for heating a boat, thus compact. [1] https://www.unforgettablefirellc.com/kimberly-wood-stove/ https://www.unforgettablefirellc.com/kimberly-wood-stove/

carapace 5y ago
That seems awesome!

minerva23 5y ago

Article: > The energetic output of an oven stove is 80 to 90 percent, compared to 40 to 50 percent for metal stoves or central heating appliances Energy.gov > Old furnaces: 56% to 70% > Mid efficiency furnaces: 80% to 83% > High efficiency furnaces: 90% to 98.5% https://www.energy.gov/energysaver/furnaces-and-boilers https://www.energy.gov/energysaver/furnaces-and-boilers EDIT: We can cut the article some slack as ducting (as typically done) does account for losses which are highly variable.

phgn 5y ago
Well, what does "energetic output" mean? If I understand the core point of the article correctly, radiant heat only heats the surface of objects not the air, so it will require less heat for the same effect. I don't how to put a number on this. I think the energy.gov article you mentioned primarily talks about heat leaking outside: > An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere.
stonkdonk 5y ago
this article lost me when I saw those numbers. It also treats heat like some kind of magic and not based on thermodynamics. heat is heat, no matter how quickly or slowly it spreads. A big thermal mass will hold heat, but will also take longer to heat in the first place. You're spending the same number of BTUs in the long run.

stormbrew 5y ago

I think heat pumps are far more likely to be a 'savior' in terms of energy efficiency and climate issues than going back to burning wood en masse, which the end of this article handwaves away even though it seems pretty obvious that it isn't really sustainable.

duxup 5y ago
And heat pumps can be fit into existing systems.
- hasmanean 5y ago
  Yeah but this “system” has advantages heat pumps don’t have. Such as the lack of a convective air circulation system.
  - duxup 5y ago
    So… then you can’t use it to heat other rooms. That’s not an advantage.
    - hasmanean 5y ago
      Yes…it’s not a solution suitable for western style houses. But maybe if you designed your entire house around the large central fireplace…it could work. I imagine that’s what they do in Siberia.
ulrikrasmussen 5y ago
Manually operated wood furnaces are also terrible with regards to particle emissions. The article acknowledges that and claims that oven stoves do not have this problem because they can reach higher temperatures. But that ignores the fact that there is a time period until the fire has reached the right temperature during which the particle emissions are very high (particle emissions from wood furnaces are scary high and dwarf emissions from cars). If the whole neighborhood is heated by these things, then you have several hours of the day with smoke and particles, even if everyone operates their ovens correctly so they reach the correct temperatures for a clean burn. Furthermore, heat pumps are just so much more efficient, as they actually move several times the amount of energy as heat as they consume as electricity. Combined with floor heating - which gives a much larger surface area for heat dissipation than these oven stoves can ever give you - you can further lower the temperature of the water, raising efficiency even more. Floor heating is also way more comfortable as it gives an even distribution of heat throughout the house, and you don't get cold feet.

14 5y ago

What I wondered about these brick stoves is how do they clean them properly? Surely they need to be cleaned of build up periodically as a woodstove needs to be done annually to prevent chimney fires.

Tcepsa 5y ago
I suspect, though I have no documentation, that they are generally built with "cleanout" access points along the exhaust path (possibly in the form of "these are the stones to chisel out if the thing needs cleaning; be sure to mortar them back into place when you are done!")
AngryData 5y ago
If they burn hot enough there should be almost no volatiles left. Most chimney buildup is from fires/chimney being too cold, improperly seasoned wood, or burning the wrong types of wood/not mixing those poor burning woods with other woods. Ash buildup could still be a problem, but would take years to build up enough to be a problem, although it likely would still need to be cleaned out at some point, although a vacuum with a proper filter could be an option or have access points built in for that eventuality.
- 14 5y ago
  I’ve burnt for years and absolutely build ultra hot fires occasionally to get ride of creosote build up but eventually like you say will get ash build up which can burn or eventually just plug the pipe. You would need access points to use a vacuum because the article showed these things zig zag back and forth to make the heat travel around the bricks. Maybe it just takes years and years since the article claims you only need to burn for a couple hours a day where my wood stove burns all day.

dukeofdoom 5y ago

These work very well. That's why I'm a little surprised none of the youtube build your own cottage videos people every try putting one of these in, and always do the metal stove. WhichI don't believe will keep you warm all night, without having to get up and add more wood. I've experienced radiant floor heating powered by a wood stove, on my trip to Europe, it was very nice. Not sure how it worked.

blaydator 5y ago

In France, https://www.uzume.fr/ https://www.uzume.fr/ is releasing open source plans for self building « batchblock » a mix between a rocket stove and a mass heater.

jkaljundi 5y ago

Strange sentence there: "In a room that is heated by an oven stove, a thermometer can hardly measure anything." Saying that as someone heating my house twice per day by wood brick oven and having multiple thermometers to measure the ambient air in the rooms warming.

jkaljundi 5y ago

Something to keep in mind though: https://www.theguardian.com/environment/2021/dec/17/wood-burners-urban-air-pollution-cancer-risk-study https://www.theguardian.com/environment/2021/dec/17/wood-bur... "Wood burning stoves in urban areas are responsible for almost half of people’s exposure to cancer-causing chemicals found in air pollution particles, new research has shown."

pygy_ 5y ago
This is less of a concern with modern batch-rocket stoves that also burn fine particles, once hot, after a few minutes, they burn without smoke.
- trompetenaccoun 5y ago
  Unless the wood is moist. Or the logs are too large. Or the wood is of the wrong kind or of bad quality. Or the stove is used incorrectly (ID10T error).
  - switch007 5y ago
    Exactly. The average user has to be very cautious. I wonder how cautious they are having paid good money for a fully compliant stove install and then think their job is over.
  - euroderf 5y ago
    Are these user-originated problems detectable using the right combination of sensors ?
    - trompetenaccoun 5y ago
      If they paid attention they'd notice it smokes. There's usually a small window in the oven for that purpose, our eyes and noses a good enough sensors for that.

ajuc 5y ago

Old rural houses where I'm from were basically a huge kitchen/dinning room build around this kind of a stove + the rest of the house. The oven heats water in pipes going through the masonry and they heat the rest of the house through radiators. And then you also use that water for bathing. So you cook in the evening so that you have hot water for bathing before going to sleep and the house is warm through the night. It also has warm shelves near the ceiling used for drying clothes/shoes/fruits/mushrooms. Very efficient, but it means the whole house is build around it.

kpmcc 5y ago
This sounds awesome.

maweki 5y ago

Just as a tiny nitpick: the German word "Kachelofen" does not translate to "oven stove", but to "tile oven" - a term mentioned at the beginning of the same paragraph.

pygy_ 5y ago

There are modern takes on this idea, with highly efficient (85%) burning cores that also burn the fine particles traditionally present in wood fire smoke, resulting in a smoke-less combustion. Plugging https://www.uzume.fr https://www.uzume.fr (site in French) an engineer and indie stove maker that makes neat products starting at €4000 for a stove kit that you build yourself.

phgn 5y ago

> Today’s energy crisis is not the first in human history. The article is from 2008, I wonder what the author refers to here. Possibly using more environmentally sustainable energy sources? Or using less energy in general?

pelasaco 5y ago

That brings me the good memories from the east Germany times, when we all spent our nights around such heaters. They were great, but I assume that would be impossible to have such things today when people want to dictate how we all should produce CO2.

tiku 5y ago

I'm still waiting on the oven/fireplace with a water pipe for exhaust fumes. We could filter it through water like a bong right? In that case you could burn newspapers, advertisment material all in your home.

tomohawk 5y ago

The rocket mass heater is the modern replacement for this. https://www.youtube.com/watch?v=fwCz8Ris79g https://www.youtube.com/watch?v=fwCz8Ris79g Uses about 1/10th the fuel, and fuel can be wood unusable in other stoves. Very little exhaust / smoke. Super efficient.

t0bia_s 5y ago

I live in center of historical city in middle of Europe. All houses are from 15th to 19th century and most od them has chimneys. In our house there are two oven stoves and we use it during winter. We are able to keep 21°C in entire house even during -10°C outside. With rising prices of gas, it is incredibly handy and saves money. House has old wood windows, not ideal for keep constant temperature inside and yet, it works great.