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Nic M


Very interesting! I had never heard of oven stoves before, but now I really want one.

Uncle B


Post (GRD) great republican depression life in the U.S. will see people huddled in smaller quarters around waste product burning stoves in wintertime. The internet has provided here, another means of survival in those days. The uber-rich will still have everything the 20th Century American citizen had, but a new class of people will not! This new class will be forced by economics, to live a more communal lifestyle and will include ovenstoves, solar, wind and wave power in their arsenal for survival. Old tires will prove an effective fuel, as will pieces of asphalt, broken furniture, waste oil and even dead carcasses. High tech computer based computer programs will help judge the amount of fuel needed daily, and feed-back items like thermistor based temperature devices will yield all the necessary data. This new class will be a very sophisticated well educated, computer and electronics savvy, biotech using, class, and will eventually overcome the uber-rich as accumulated wealth from earlier times is used up, and will develop a greener sustainable renewable way of life for all survivors! America is in for cataclysmic paradigm shifts and ovenstoves will play an important role.



You know,I dont know how to explain this shortly...
But the thing I miss here is "planting willow trees".they grow extreemly fast and produce good firewood. NOW we are talking real C02-neutral heating.

Somebody please make a link to these english monestaries where they've been heating with willows for ages.

Ed Magowan


This meshes well with another interest of mine, woodgas stoves / generators. I no longer live in a climate in which an oven stove would be useful but that may not always be so. I cook with a woodgas stove and hope to build one capable of running an electric generator.



"In Finland, a major producer of soapstone heaters, the purchase of an oven stove is subsidized by the government, with the consequence that 90 percent of new houses has them inside."

I was wondering where you got that figure. 90% seems wildly exaggerated - even if you include pellet stoves, open fireplaces and the like.

kris de decker


It's a number that turns up in several sources on oven stoves, both in English and German. However, I can't read Finnish, and my request for more information was not answered. So it might be promotion talk. It would be great if you could provide us with more accurate figures on that!

Robert Speirs


Nothing "deserves to be subsidized by the government". That is the surest way to kill any development. And if it were "deserving", that is, worthwhile, why would it need other people's money, taken from them by the government at the point of a gun, for it to be useful and helpful??

Ric Locke


The other advantage of a tile stove is that the stokehole need not be indoors. This means that the servants can feed the fire from outside, or from an adjacent room, and the Prince can be warm without having firewood carried in and ashes out over his beautiful carpeting, not to mention avoidance of dealing with the lower orders. Ludwig's castles are full of that type. No doubt Uncle B's will be also, when he gets that far along.


kris de decker


I have received some private reactions that might be noteworthy.

First: according to some, an oven stove only makes sense in a low-energy house or passive house. In a normal house most radiant heat will get lost through the walls and the windows. In that case it will be hard to maintain a temperature higher than 17 degrees Celsius.

Two: it is not always easy to retrofit an oven stove in an existing house - most new buildings do not even have a chimney.

kris de decker


Here is the answer from Tilastokeskus, the Finnish office for national statistics:

"The Finnish government does not support the installation of oven stoves in Finland. We have no figures of how many new houses are equipped with oven stoves nowadays. In 1990 the figure was somewhere around 75 percent of new houses (unofficial figure from an official of Ministry of Environment). By the way, 'tulikivi' is a trademark. A better Finnish word is 'tulisija' or 'takka'. Best Regards, Kirsi-Marja Aalto."


Thanks to Klaas Van Gorp for bringing me in contact with the right person.



A oven stove does not heat by infrared radiation. It is a radiant heat source (like an old style water filled radiator), but the exterior temperature of the stove is not enough to generate any real infrared radiation (goood thing, too: a stove that hot would be an incredible danger to people, especially kids :-)

Those things you put in your patio (fired by GPL) heat by infrared, but they are glowing hot...



I'm not sure why commenter #11 believes that these stoves do not heat via infrared radiation, because they definitely do. Long-wavelength IR if we're to be more specific. The LPG heaters with glowing elements emit radiation with about 1/3 the wavelength of that emitted by masonry heaters.



Loved this post but Robert Speirs comment #7 was exactly right. Government is the surest way to destroy a working economy. Individual rights must be respected--and this is the best way to help the lowest income earners as well. Give them a chance to rise out of their poverty. Do not steal from those who provide them that chance. Don't kill the goose that lays the golden eggs.

Eric H


The comment at 11 is wrong. Infrared radiation is generated by all black body radiators with a temperature greater than 0 K. Comment #12 is correct, something which is hot but not visibly glowing is emitting a great deal of IR energy in wavelengths longer than those visible to the human eye. The energy emitted by a black body forms a continuous curve with a recognizable peak. Regardless of where the peak is, the energy as a function of wavelength is a continuum. As I recall, the Planck curve corresponding to room temperature (~300 K) peaks at about 9 microns, which is considered to be "long wave IR" (LWIR). The peak moves toward shorter wavelengths as the temperature increases. The Planck curve corresponding to the sun (roughly 6000 K) peaks at around 0.5 micron, well inside the visible range (roughly 0.400-0.800 microns).

See the Planck curves in this article:

Note that black body radiators and line emitters (such as gas combustion) are different.

I would also agree about the subsidies. Far more useful than subsidies would be changes in building codes that would allow for alternative methods like this, as well as reuse of grey water, etc.



I happen to know the German wood stove product featured last. It has a computer controlled air intake, leading to a very efficient combustion process with little wood required. The system is also modular, supporting cooking, water heating and thermal storage.

Mark McClure


You know, I'm surprised by the idea that Americans didn't go for this type of stove back in the woodburning days. Sure, firewood may have been plentiful back in the pioneer days, but it takes a lot of somewhat dangerous work to cut, split and stack wood. You'd think the efficiency of this stove would outweigh the cheapness of the fuel.

- Mark in Santa Barbara



Korean Ondol under floor heating is traced back as far as the Bronze Age. When I was stationed there, I LOVED my apartment's steady and even heat! Although mine was oil fueled, older small outdoor charcoal burners worked surprisingly well using just a very small stove and fitted charcoal round "bricks."



These masonry heaters are perfect companions to TLUD (top-lit, up-draft) wood gas stoves. The TLUD prefers to burn wood chips and finger thick branches that are usually referred to as yard waste in the US and are therefore free. Literally, huge piles of woodchips are left around my town by the city's tree pruning crews to be spread as mulch.

The TLUD stove burns very clean as tars are destroyed by a bed of hot charcoal above the flame front. What emerges from the top is hot producer gas that will burn if provided with a supplemental oxygen source.

Combine the hot clean fire of a TLUD with the large thermal mass of a masonry heater and you have the ideal heating appliance; a clean, efficient, heater, that works with free fuel. How sweet is that?

Dave P


If one is to use wood as a heat source these would definitely be better than conventional wood stoves in the US and Canada. Although I would probably not recommend wood burning as it has been identified as a major air polluant. Montreal had its share of bad air quality this past Winter!



I can help you I am born and I grow up and live my 42 years with "Kachelofen". In my house we have one in each room, diferent size and designs, In the beginnings we heat with wood, but than in th early '60 my father change for 'gas methane', it is so comfortable, no allergies, pleasant heat. In the living room the Kachelofen was like a chair, and when you came tired and have cold is so wonderful to stay and warm there, or to heat my pillow before go to sleep. I wish you all to have only one in your home and you will see that nothing compares!
The wood, I know that Montreal burn hectars of forest just for the fun and the result is smoggy days, but , instead of "openfires" that just burn the logs, pollute and then you smell like somebody comming from camping, imagine you put just ONE log in your kachelofen, close the little door and you have warm all the night!...because after 1 hour your log is burn, but the hot embers stay till the next morning and heat your kacheloven.
So, no more pollution, no more smog, no more forest burn for nothing and you are burn on a side and freeze onthe other side.
And they are so beautiful .



My wifes family in Ukraine had two of these stoves that they used to heat the house. Sadly, a few years ago a natural gas line was run through the village and they dismantled the stoves and started heating with gas. I told them to leave the stove as they might need it, but lighting it is a chore that you don't have when you can just crank up the gas heat. I don't forsee the stoves being used in North America for the same reason. The reason conservation is not so widespread is because companies don't make money from conservation.



In Romania they are very popular also. They are called SOBA DE TERACOTA. And they are heated by wood or gas, especially in cities. There are a lot of companies with a lot of experience which are producing "cahle"; these are the tiles in many shapes and colours. But most important are the special bricks you put inside, the name is "shamota" (chamote) this is what keeps the heat for a lot of hours.

This winter, for example, especially in the middle of Romania it was vey cold, about two weeks of -32C, but the people were not afraid because they had enough wood stock and they heat their homes by "teracote".(kachelofen, tiles stove)




Here is the short article with very useful links on stoves. I do build (assemble them is more appropriate term). It is very very physically demanding job. I need to build one this or next week for a friend.



Just a minor linguistic correction; The website states “the German term “kachelöfen” (oven stove) describes it best as an umbrella term.” Actually, Kachel in German means tile, so “kachelöfen” would be tile-oven.

I lived in West Berlin in the late 1970’s in an apartment with a “kachelöfen” as the only heat source. We heated it with coal bricks. Each apartment in the building had a small space in the basement to store these coal bricks. The coal bricks were delivered by truck into a chute opening onto the street. Also, there was no hot running water. Instead, there was a five liter tank above the kitchen sink that was connected to the cold running water source. After filing this tank you could press a button to bring the water to a boil (using electricity) and then mix it with the cold running water. Many people lived in such apartments at this time.



There was a story in Britain's Daily Mail newspaper about them a while ago mentioning the efficiency of them. Apparently the man who built it was born in Eastern Europe.



There is one more type of efficient wood stove: the rocket mass stove. It uses the same principles, but the heat is stored in cobb benches or walls that the flue passes through. (Cobb is a composite of sand, clay, and straw.)

The only source I've been able to find is a book called Rocket Mass Stoves: Super-efficient Wood Stoves That You Can Build by Ianto Evans.

I am not affiliated with the author, but I am building one. Total cost for mine will be less than $50 USD.



I keep coming back to this article as the idea seems very sensible, esp. for rural living, although I have already built my house and it is not really retrofittable to a masonry heater.

One thing that occurred to me was "how do you clean out the flue" with that complex smoke path? Perhaps the combustion is so complete that there is little build-up?

Clara Vass


In Central-Europe, in Hungary the oven and the glazed-tile stoves has a rich and long tradition, too. I suggest the home-pages: www.majorkandallo.hu and www.vilmos-kalyha.hu - a builder of glazed-tile stoves and traditional ovens and a designer and an owner of a glazed-tile manufacture.



I use a masonry stove myself, and I like your site, but I disagree that a basic need to heat a home needs to be "subsidized by the government." I built my own stove and paid for it myself, and I'll be damned if I think it right to bilk my friends and neighbors for my own personal benefit. We do not own each other.



What about Geothermal heating?

hugh owens


In our old log cabin we recently replaced the antique wood cookstove with an Amish built "kitchen Queen cookstove and we placed about 1000 lbs of concrete paving blocks around the perimeter . The stove itself bakes beautifully, cooks better than a gas or electric stove and heats the heavy mass of concrete such that it is still warm in the morning. It heats our house wonderfully. It is a long way from an oven stove but it was a wonderful purchase. We bought it from a dealer in Montana.



We have lots of these in the Northern Finnish houses where the temperature gets as low as -38C in the winter. The heat that radiates from them is amazing and lasts long after the fire is out.



The article mentions the fact that these stoves are expensive and require craftsmen to build. Might I suggest the Cob stove? Inexpensive, and a careful beginner could build a stove over a couple of weekends. http://www.richsoil.com/rocket-stove-mass-heater.jsp



I loved the article! Rob (poster above) is correct, the rocket mass heater would be an inexpensive alternative to the gorgeous stoves in the article.

David Remus


"If a wood or gas stove is overheating the room, you simply turn it lower and the temperature goes down fast. With a tile stove, this is impossible to do."

"A third disadvantage of the tile stove is a consequence of radiant heat. An oven stove only heats the room where it is positioned. Opening the door will not warm up the room next to it, because it is largely lying in the “shadow” of the radiant heat."

If you placed the stove in the center of the home with the walls dividing the rooms radiating out from the stove, thereby dividing the home into quadrants of heated space and effectively having multiple heaters, you could selectively heat rooms by covering them partially or wholely with an insulating panel. The heat NOT radiating out into an unused room would translate into a longer heating time into the rooms being used.

And overheating is a problem easily solved. If you simply cover part of the oven stove with any insulating material heat resistant enough to not degrade, you have effectively reduced the size of the radiating surface to whatever level you are comfortable with. The side effect is a longer heat time.

The material could simply be a thick wool blanket, or any such insulating material so this solution could be applied to a stove built hundreds of years ago for the price of a couple of nights out. Even aluminum foil would reduce the radiation.

Infrared reflects off of certain materials so heat CAN be directed into another room. Overhead and over the wall, etc.

David Remus
Clovis, CA

Fernando (Ph. D. Engineering)


Nice article but the thermodynamics of heat transfer is a bit muddled. Comment 14 is addressing the relative wavelength distribution of the light emitted by a blackbody object. He is neglecting the Stefan-Boltzmann Law that states the radiative heat emission per unit area of an object is proportional to the temperature of the object to the fourth power. The net radiant heat transfer is proportional to the fourth power temperature difference between the object and its surroundings. Roberto is correct that colder higher surface area stoves transfer more of their heat by convective and conductive processes (molecular collisions) than radiative processes. If you assume a stove surface temperature of 50 C and a surroundings of 15 C, an emissivity of 0.9 for brick you get a radiant heat transfer rate of approximately 200 watts per square meter, this is too low to account for 90% heat transfer for stoves that have outputs of 15 to 20 kW, even with 10 square meters of surface area. For a hot surface ( iron) stove at 250 C the radiant heat transfer rate is 3500 W/ m2.



I looked into having a masonry stove put into my house when we built in 2007 but here in lower Michigan I couldn't get a quote from a builder of masonry stoves for less than 15k, and the place wasn't too responsive even at that. With the baffles it didn't look like any home project either for a first timer. So I got an efficient soapstone wood stove for 1/3 the cost.

Mrs. C


I want one. Does anybody in Arizona, USA build them?

Debra Callahan


http://www.mha-net.org/certified-heater-masons/ Matt Helicke built one in So. colorado for us. We love it. So worth the cost. I have sinus problems and it does not dry out my sinuses like gas forced air or wood stove. We would have cut anything else in tne house in order to keep the heater. We have a bake oven I use every day.

Fireplace lover


As mentioned earlier, Tulikivi is trademark and not general term for this apparatus. Neither are tulisija or takka any better terms because they describe more open fireplace. Actual finnish name for this is 'kaakeliuuni' or 'leivinuuni'.
Kaakeliuuni is for heating only and leivinuuni is for making baking bread and other foods on top or inside the thing - as well as for heating.

Pretty much every old and modern house in Finland has at least a fireplace. Some fireplaces circulate heated air around inside heat absorbing elements around the fireplace or even under the floor using a heat exchanger before it leaves the house.

My understanding is these oven stoves are coming back and are built more and more into new houses. Which is nice.



This is how rocket mass heaters (RMH) work. They heat the home by heating the mass, which radiates heat long after the fire is out. Rocket mass heaters can be built by the home owner fairly inexpensively, require much less fuel than metal stoves, and burn so efficiently that no visible smoke comes out the flu after it has come up to heat.
Another article featuring rocket mass heaters would be in order, I think.



lf I were to take a small steel stove and 10 odd meters of mostly corner chimney ducting making a convoluted route for the smoke to take before reaching the existing fireplace chimney then bury the whole thing in earth, I would have one of these oven stoves?



I have a friend who built these stoves into two homes in upstate New York. With the right room layout at the time of the build they can heat every room in the house. He still uses it as his main heat source after 30 years.



Hey Kris, a long-time reader here!

As a tile stove enthusiast and a long-time user of one, I loved this article since it came out, and have finally decided to give my input.

So, I grew up in Croatia in a compact 1950's apartment with a wood burning tile stove in living room. The stove was about 1.6mX1mX0.6m in dimensions, we call them "Kaljeva peć" and they are very, very similar to DDR-period Kachelofen.
Based on this, i'd like to fill in on some things you mentioned.

1. STOVES HEAT MUCH FASTER THAN YOU MENTIONED. from stone cold to hot takes about 30 minutes. that's it.
Perhaps for some super big ovens it takes longer, AND when the stoves are NOT CLEANED (or made in a bad way) you have problems with heat transfer.
however, this isn't fault of technology itself and i have to make this clear!

for example, a few years back i was bunking over at one place in Berlin which had a similar stove. however, it simply wouldn't get hot although draft was good and i fired it a lot. why? because i recognized the inner flues were dirty and partially clogged.

2. these stoves CAN (and WERE) used to heat the entire apartment of 56m square. you do this by simply keeping doors of other rooms open, and while rest of apartment isn't as hot as the room with the oven, it's temperate enough to be comfortable with a bit of normal winter clothes, like a sweater and wool socks.

3. the heat isn't only radiant, it really, objectively rises the indoor temperature because the radiant heat heats up furniture, walls, etc.

Aside of the advantages you mentioned with less dust (i can attest to that being true) and of "healthier heat" (my cousin and grandparents always loved our stove and they lived in a place with central heating), the two biggest advantages of these stoves from my standpoint are fuel flexibility and fuel autonomy.

FUEL FLEXIBILITY - you don't only use firewood but can burn essentially any wood inside. I sometimes collected park wood which was cut in neighborhood. you can use wood debris or cuttings from a sawmill, or coal, wood briquettes, all work fine on a well built and maintained stove. also, you can give (or be given) some fuel by your neighbors in a pinch. you can't do that with electricity.

FUEL AUTONOMY - you prepare the firewood for winter beforehand, in summer. especially if you're on poorer side, you will have time to plan your finances, see your options, and have time to cut and stock everything up. so, when winter comes, you know you're set. compare this with gas heating, which you need to pay on spot, and where you are dependent on price the provider dictates! such ovens are a blessing for low-income people!

I'd like to touch on the stoves being complicated to build. most stoves are indeed a bit challenging as you have to make complicated flues, have special firebricks, mortar and etc.

so, what are the options for interested people without a big budget, access to craftsman or a lot of skil? well, firstly, don't go by the stoves you see if you type "masonry heater" in google, they're too complicated to build and also ridiculously big.

and also, dont be discouraged,because there are a couple of options:

1. a double bell Kuznetsov stove. it's very simply designed and still retains a lot of heat.

2. brick cookstove/heater: google "sesselherd" for Austria or "sparhelt csikótűzhely" for hungarian examples. Austria and Hungary have great designs.

3. in many pannonian villages you have simple mud stoves (google "bubos kemence") which are stoked from outside with whatever is available, including corn stalks, reed, hay, brush, cleaned corn cobs, etc. and that can be interesting on a homestead. these stoves are made by rolling clay cylinders on a wicker frame and are essentially a large, tall bread oven. there are pictures and videos online and it's not really rocket science.
your room will be a mess for a couple of days when building it, and you will have to let the clay dry for a month or so before first stronger firing. also you will need to apply and renew each year an inner protective layer of the stove made with a mix of clay, horse manure and shavings so it doesn't start smoking up the room. but if you do that, they can last for 50+ years and are pretty cheap and simple to build, can be fired with agricultural waste and you need to fire them up twice a day, or three times if it's really cold!

Good luck to everyone trying to built their own! I can only recommend it!

Stefan Erb


Thanks, Marko,
for your great comment.
I totally agree.

I think, Kris, you saw the oven stoves worse than necessary and than they actually are. That speaks for your honesty and extensive research. Well done!
I'm not so sure about the combustion quality of a rocket mass heater, as the fire doesn't achieve a high temperature firing only little sticks.

John Wesley-Knox


Slowburn: Based on a number of presuppositions (which may or may not be warranted), I would say, "In principle, I think you would".

Tobias Boyd


A great read, though I was surprised not to see any mention the Chinese kang: https://en.wikipedia.org/wiki/Kang_bed-stove



Just a couple of sources for more info about rocket mass heaters, as some of the comments were looking for.
https://permies.com/w/rmh-resources (a great starting point as they link to lots of other rocket mass heater resources)
https://freeheat.info (info about rocket mass heaters, a movie, and plans - things like a rocket kiln, sauna, and regular heaters)
Rocket mass heaters are incredibly efficient, with minimum inputs (both materials and labor) and can be built yourself, so often very cheap to make and run. They are also good for the planet with a clean burn, minimal use of materials and made from natural and often recycled products. And they can be good for community building, not only through projects to make them but also as they often have a long bench built into them (the mass) which is conducive for gatherings/socialising. It would be great for more people to find out about them, especially as so many are struggling right now with the cost of heating conventionally. Hope this helps!

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