I am just wrapping up a very high end sauna build in a primary bathroom in downtown chicago, and I used trumpkin's notes as my bible/guideline with this build because it seems to be the most reliable source of accurate information. I am very grateful for the work that Mr Angell put into it.
“We don’t go by denying anything, but we go by lifting the experience…” Tremendously wise. I come from that camp too. If we think we’ve arrived and our way is better than another’s - we’ve missed sauna/Inipi (sweat lodge) main teaching: We are all just common humans journey earth. Who are we to judge?
Just a clarification, any mass can "radiate" heat and can also conduct heat. The difference between materials is the rate of radiant or conductive heat the type of material can emit. Steel emits rapidly and "harshly." Rock and masonry don't emit radiant and conductive heat as rapidly as steel. And wood emits radiant and conductive heat far more slowly... Steam moves around the room as "convective flow." Heat rises. Gas, when it is heated, has the molecules expand further apart from each other and that causes the lower density, hotter gas to rise. When you throw water onto a heated mass to generate steam, the water turns to the vapor known as steam. This happens as the mass "conducts" the energy into the water. No matter how hot the rocks are, the steam will NEVER heat higher than 212 F at ambient pressure. The difference in steam is as more energy enters it, the water molecules push further apart. And the further the molecules get apart, the more energy has to be extracted before they condense back out to water. This is associated with the "dew point" in the room. A big difference in sauna quality is the temperature of the stones used to make the loyly steam. Rocks barely above 212 F don't "flash" the water to steam rapidly (resulting in less convective energy) and result in "wetter" steam that condenses out more easily (closer to its "dew point"). Superheated rocks (still needs a better definition, but likely 300 F+) flash the steam rapidly, cause the water molecules to separate further. And that requires more energy to be released from the 212 F steam before it condensates out on surfaces as 212 F water. The further apart the steam molecules are, the more thermal energy they carry to transfer into the mass of the room (including your body). But also the more widely spaced the water molecules are to slow the rate of conduction of the heat from the water molecules to your skin... Wet steam will conduct heat into your skin faster, which isn't as Finnish Sauna "comfortable" as dry steam loyly more "gently" (or "softly" as the Finnish describe it) conducting an even higher amount of thermal energy into your skin. A key thing people don't seem to understand about sauna heat transfer, is that convective heat flow leading to conduction of heat from the loyly into your skin, really doesn't penetrate very deeply into your body. The wavelength of the heat is different from "radiant" heat. Radiant heat is more comparative to microwaves that penetrate the mass (You may already know that microwaves cook from the inside out, whereas conductive and radiant heat cook from the outside in). Raidant heat is key to raising your core body temperature in combination with a high enough dew point in the room that prevents sweat from efficiently lowering your core body temperature. So radiant is a KEY part of Finnish sauna too, right alongside of the convective hot air and loyly movement. But Finnish saunas (going back to the historical Savusauna design) "traditionally" use high wood mass pre-heated for pervasive but gentle radiant heat cloaking your whole body from all directions as emitted by the wood mass surrounding you. This is the good heat that the Finnish regularly describe but don't always understand the physics of. You also feel the complexity of the conductive heat coming off the wood into your skin. The other essential part of good Finnish sauna is the convective flow of the hot air and the loyly steam. This "moves" the hot air over your skin, and the water molecules conduct into the skin. The skin is where the heat and pain sensors are. The heat on skin is a VERY sensual experience, much more so than the radiant heat penetration into the core of the body.
I very much agree with Walker on the design of Finnish convective airflow and what Walker calls the "convective loyly pocket" above the height of the rocks. And the criticality of having the outlet vent below the top bench and far away opposite of the stove to preserve the heat and to not disrupt the convective flow. And also Walker's promotion of higher ceilings to help optimize a strong convective flow. There should be minimal air mixing in the strata isolated below the height of the stove rocks and the convective loyly pocket above. The added air volume of a higher ceiling, therefore, doesn't really shift the volume of air you are heating for the benches where people sit. The higher ceiling also limits convective airflow disruption as people enter and leave through the door. Walker was the one who brought this to everyone in North America's attention, including getting me to think about it, and he is spot on with these convective airflow and sauna hot room optimization observations. 3 tiers of benches with the feet positioned above the rocks on the top 2. The bottom bench being for those who need to cool down a bit, with most of their body and their feet below the rock height and out of the loyly cavity. In my future build, I am planning to ramp from the door up into my hot room to further lower the door as compared to the convective loyly pocket, to further preserve the heat flow.
Some of those old-timers in the U.P. might be building with the same principles. We built our sauna hot room 10 foot tall after using saunas around North America.
Hello @pigstuck …I have many question but I’ll try get a answer to just this one. We are building and have the option to go 10’ instead of 8’. Why do these graphs I’m seeing show higher heat at taller ceilings. Obviously heat rises but there has to be a cut off when the returns aren’t higher temps with higher ceilings? We have the Kuma stove,and are building sooon. Hope this message finds you or anyone that cares to answer. I appreciate any input
@@raquelmillard9701 There isn't one right answer for sauna builds, but if you have a large enough footprint and can navigate steps or a few benches, I usually recommend going taller. For one, you lose less heat when you open the door. We built a 10' sauna and enjoyed it. But even 8' will still be good.
@@raquelmillard9701The key to achieving and maintaining the heat you want is the sizing of the stove for the air volume and thermal losses (e.g. windows) of your hot room. A taller room requires a stove that can heat more volume. Over sizing is better. You can always ventilate more to bring temperatures down. But you want to be able to hit your target temperatures and you want your stove capable of overheating the rocks.
I want to build a Finnish style backyard sauna heated with a wood heater. I have read and watched lots of material so I know about the need for ventilation etc. For reasons of space, cost and heat up time etc a 5' L x 5'W will be big enough. Watching this video I now wonder what ceiling height I should have. What is your advice? thank you
From the convective flow studies I have seen (and still need to properly gather and document), there is a minimal and somewhat disruptive (turbulent) convective flow effect on lowering the loyly cavity when stones surrounds are used on the sides of a stove. As I conceptualize the convective airflow, the lower the heat rise starts, the more the inlet air from the vent by the stove and under the door will interact with and interfere with the strength of the convective airflow. I look forward to testing this hypothesis with hanging feathers and non-toxic colored smoke to "see" the strength and direction of the airflow. Ruspar, who I enjoy corresponding with) has posted some similar convective airflow analysis from Banya. I just do NOT see the value of high stone mass on the sides of stoves. It likely slows radiant transfer to the wood mass in the room (thereby likely making it longer and harder to get even temperatures emitting from the wood in every corner of the room). And such a lower convective airflow loop is likely even more prone to turbulence and disruption, than having the convective loop "up" in a proper loyly convective cavity as Walker wisely proposes will optimize sauna performance. But if you are "stuck" with a low ceiling, then I guess any incremental improvement in the loyly convective loop will be welcome??? But at what trade off in regards to radiant heat up times for the walls and benches? I want that enveloping, deeply penetrating radiant heat such as you get off the wood walls of an old school savusauna. I don't like saunas that only heat me "skin deep" with nothing but convective airflow and the associated loyly... It takes much longer to transfer heat into the mass of wood with convective and conductive heat flow, than it does with radiant heat flow. Radiant heat flow efficiently penetrates deeply into the mass. And, reiterating, this is what "I" find wrong with the modern, urban style electric Finnish saunas so prevalent today. The hot rooms are tiny, so any radiant emissions from a stove are uncomfortably too close to bathers. And the builds have comparatively little wood mass to properly and gently "radiate" heat anyway. So these modern, urban Finnish saunas eliminate the "traditional" role of raidant heat in the hot room and rely solely on convective currents. And I guess with thin wood cladding that may be all you need to heat it with as little heat as it can receive and radiate? The marketing campaigns to drive exports have convinced even quite knowledgeable "sauna experts" that minimizing radiant heat is a good thing, when I'd say it is not... It certainly isn't "traditional" Finnish sauna design; it is a VERY modern approach. But cheers to anyone who actually prefers the modern "skin deep" heat experience of such "modern" Finnish sauna...
Also, if I was looking to build an authentic sauna room on a smaller scale at my home, are there any builders within the United States? For example, like cedar and stone that could be contracted for such a project? Any advice on in my research would be very appreciated. Thank you.
Absolutely svelez - depending on where you are located I would start with contractor/carpentars that could assist in a custom build or there are many ways to go about doing something yourself. You would be surprised what you can do with a nail gun and a shop saw :) Good luck in your searches.
Great podcast and a lot of great points raised. I realize I'm rather late to comment, but here goes. Regarding "heavy steel sauna stoves". If you want to have a reliable stove that will last a long time, the firebox part of that stove must be heavy steel. Minimum 1/4" thick. 3/8" is even better. Now. There are ways ways that you can can shield the sauna bather from the harsh, high emissivity, of the hot steel. - Fire brick within the firebox itself - Using a side-mount hot water tank (also great for bathing purposes) - wrapping the sides of the stove with "rock cages" (this is popular with IKI, and is now becoming widely adopted by Harvia, and even Kuuma) - installed heat shields that are mounted to the stove itself (a long practice of Kuuma, and now becoming more common on Harvia) - installing heat shields mounted to the walls of the sauna room (these can be steel, or even brick) The main purpose is to shield the bather from the harsh radiant heat. Distance helps too, but this can be tricky to achieve in smaller rooms. The one area of the stove that is more difficult to shield would be the door of the stove. An insulated door helps in this regard. Another solution would be exterior feed, since you can "treat" the other 3 sides with solutions listed above. Others have pointed out that rock and even wood can radiate heat. Just at a lower emissivity, so I won't go into detail here. Similar to Eero's opinion, we should not be overly critical, but try to educate. Branding on type of sauna as "not a sauna" or one manufacturer as "not a good stove" is not the point. We should aim to educate and instruct those on how to make the best possible sauna. How to improve the sauna they have, or the stove they have. There is never really a perfect one, since sauna design will always have some form of compromise. Oh, I wish I had unlimited budget where I could do nothing but build and play with designs. So much fun. This is why we all nerd out on design. Always chasing the "perfect" sauna. But really, the best sauna is the one you use often, in good company, and with good food. Time for sauna.
He neglected to measure the CO2 levels in his house, which is a significant oversight. Without accurate measurements, he is relying solely on subjective feelings rather than factual data. It's worth noting that individuals working in grow rooms with CO2 levels at 1600 ppm experience no issues and function normally. In contrast, the average CO2 levels in a typical home are around 1000 ppm. Given his inability to understand and manage basic CO2 levels, it raises questions about the reliability of other information he or his website provides.
I have a Thermory barrel sauna w a Huum Hive 13 wood burning stove. I truly enjoy it, and it was a fun project for me to build. However, I don’t feel as motivated to use it as the daily temperatures go higher into the 90’s. How do you maintain your dedication to using your sauna in this climate while still managing to enjoy it as much as when it’s cooler outside? It’s just not as pleasant to me when it’s hot outside.
It's a pretty foreign concept to Americans, but standard practice for the Finnish. We wear suits when we are in town or in mix-gendered company. - Risto
But all 3 types of heat flow optimized properly and working together is what makes good Finnish Sauna. You do WANT good, gentle radiant heat. Savusauna is filled with gentle radiant heat!!! That is as "traditional" of Finnish sauna you can get. Only modern (light weight for shipping) sauna kits ignore radiant heat in favor of focusing primarily on the "skin deep" convective heat. When in fact, radiant heat is THE heat emitted by the burning wood that is then transformed into conductive and convective heat. Early, "traditional" stove saunas were high radiant metal stoves radiating and conducting thermal energy into stones so that the smoke could exit the hot room through a chimney instead of filling the room from the savusauna style stone hearths. This added higher radiant heat emission rates (harsher heat) from the metal... which was buffered by distance from the bather and by the rocks. As stoves evolved to steel, they added heat shields to direct the radiant heat away from the bather, and focus the radiant into a jet of upward moving convective airflow. Note that all stove heat (electric or wood burning) is using radiant to generate convective heat. You don't get strong convective flow without radiant heat. The key is channeling the radiant through good engineering design, NOT avoiding radiant heat. What you want is avoiding harsh radiant heat directed at the bather during use. The Finnish commercial marketing push for easily shipped and exported light weight sheet metal stoves with low radiant heat emissions is a "modern" version of sauna that has little resemblance to "traditional" Finnish sauna from a Physics thermal energy flow analysis. Without heating a considerable wood mass surrounding the bather (which doesn't happen with thinly clad wood walls) to emit raidant heat deep into the body core, the sauna heat provided by the convective airflow is literally only "skin deep." With such a low radiant heat sauna room, you then have to rely on humidity levels close to the dew point to keep sweat from evaporating for the core body temperature to ever rise. At that point, you are closer to a Hammam experience with steam bathing, than you are to a Finnish Dry Sauna! So, from a physics standpoint (science) I argue that "traditional" Finnish sauna requires the high radiant heat output of a well designed heavy steel wood burning stove, that is capable of heating up the mass of the room and capable of flashing superheated steam off of superheated rocks. The sheet metal electric stoves may produce good loyly, but they don't produce good radiant room heat from the wood surround. Yes, they provide a "modern" variation of the sauna experience well suited to bulk usage in an urban environment. But, no, they are not actually "traditional" Finnish sauna regardless of what the export marketing promotes. Study and understand the thermal energy flow differences between truly "traditional" Finnish sauna and the "modern" sauna style Finland is exporting as "traditional" and it becomes VERY obvious the challenges associated with trying to match the amazing sauna experiences you get in Finland. The "best" saunas all have high thermal mass of wood getting "soaked" with thermal energy for gentle, cloaking radiant heat flow into your body. That is hard to replicate with a sheet metal electric stove. The SaunaSherpa (Kimmo) in Finland and I were discussing this on Facebook the other day. He absolutely concurred with everything I outlined in these comments. Radiant is not only good, it is CRITICAL to proper sauna. Banya evolved a different style of masonry shielded stove at extremely high mass for even greater radiant heat emissions. And many commercial Banya and Shvitz hot rooms are concrete or masonry walled for a different feel of the radiant than wood. But the "traditional" Banya was a log structure, evolved from the common ancestry of Savusauna. Banya and Shvitz still throw water for steam, but don't seem to design the convective airflow so intentionally as Finnish sauna design. The Banya benches are high like many savusauna platforms above the stove were/are.
Serious question, I am looking into building a wood burning heater sauna out of a 20ft shipping container. Is this something that can be a legitimate Finnish style sauna? I am American but used to Live in Finland and became obsessed with sauna’s. Thanks for the help in advance.
Absolutely! A 20ft shipping container can indeed house a legitimate Finnish-style sauna. Make sure to ensure proper ventilation for an insulated wood lined hot room, and consider adding a changing room for comfort. Specialty container vents can easily be purchased online to help keep water and pests out. Take inspiration from Sam, one of our hosts, who converted a container into a hunting cabin using a sauna stove. Good luck with your project!
Hello upper bench thank you so much for your good work and commentary. I am new to sauna, and was wondering if any of your panel could suggest an authentic FINNISH experience somewhere in the United States that I could take a vacation to experience with my wife the proper way?I really want to experience authentic sauna as I have never done that before. Can you please suggest a location where this could be had? I currently live in Georgia, but can travel anywhere within US
Hi, Risto here. I'd be happy to recommend some authentic sauna places in North America. If you have Facebook, send me a message on our Upper Bench page... or you can email me at cjrice@gmail.com.
Had my barrel benches raised and added more rocks. Main tip after that: don't get in too early. Best experience is when the third wood portion has burned.
And I find it VERY misguided when wood fired stove manufacturers follow that lead towards limiting radiant heat emissions with stone surrounds. It is all because most don't seem to understand the complexities of the interplay of Convective, Radiant, and even Conductive heat towards an "optimized" and "traditional" sauna experience. The discussion in this podcast is a perfect example... Respect for your sauna expertise, but it is not thermal flow expertise from understanding the physics involved.
Do you think Infrared Saunas suffer the same Carbon dioxide issues as traditional saunas. All of the Infrared saunas I see have holes in the ceiling and bottom of the sauna behind the bench. Do you believe they should use Mechanical downdraft similar to traditional electric saunas?
Hello Lukezier9616, thank you for the comment. Measuring would be the surest way to tell and vent holes probably help some. As a side note, we don't consider infrared to be a sauna because it is missing the core element of sauna... löyly!
I recently posted on Facebook how isolated emigrants often preserve historical cultural knowledge better than their home countries do. Anthropologists seeking to understand historical Scottish dialects and customs go to Appalachia to study local Scottish immigrants, because their language has evolved less and their customs have been better preserved than in Scotland. I hypothesized that the same likely happened along the banks of Lake Superior with Finnish immigrants. And descendants of the Finnish immigrants in America jumped into the thread to post examples that support this theory. And one prime example is the Nippa, Kuuma, and Fenno stove designs. They "are" more traditional than most widely sold current Finnish stoves. And they focus on a more "traditional" sauna construction style that includes the role of radiant heat from the surrounding wood mass, just the way savusauna did and early metal stove saunas in Finland did. This may not be politically correct amongst the sauna societies, but... In my opinion, you can get a more "traditional" Finnish sauna experience from such a Finnish-American sauna stove builder in North America than you can by importing a more "modern" style sheet metal sauna stove from Finland. And Finnish sauna experts like the SaunaSherpa in Finland agree with that assessment. The truly GREAT Ginnish saunas he shares with guests on his tours, are not fired by "modern," urban mass-consumption sheet metal stoves. And they are not thinly clad small "closets." They mostly have powerful wood burning heavy steel stoves, and they have high thermal mass of both stones on top of the stove, and and heavy wood on the walls. And they have 3 tiers of benches with higher ceilings and feet above the stones... "That" is great "traditional" sauna, and that is NOT what Finland is exporting as "traditional" sauna. And it has GREATLY confused the North American Finnish Sauna market...
I am just wrapping up a very high end sauna build in a primary bathroom in downtown chicago, and I used trumpkin's notes as my bible/guideline with this build because it seems to be the most reliable source of accurate information. I am very grateful for the work that Mr Angell put into it.
Great to hear! Let us know how it turns out after you've used it for awhile
“Primary” hahaha. It’s “Master.”
trumpkin revealed! been so very helpful, from narnia kiitos
you are most welcome :-)
“We don’t go by denying anything, but we go by lifting the experience…” Tremendously wise. I come from that camp too. If we think we’ve arrived and our way is better than another’s - we’ve missed sauna/Inipi (sweat lodge) main teaching: We are all just common humans journey earth. Who are we to judge?
Just a clarification, any mass can "radiate" heat and can also conduct heat. The difference between materials is the rate of radiant or conductive heat the type of material can emit.
Steel emits rapidly and "harshly." Rock and masonry don't emit radiant and conductive heat as rapidly as steel. And wood emits radiant and conductive heat far more slowly...
Steam moves around the room as "convective flow." Heat rises. Gas, when it is heated, has the molecules expand further apart from each other and that causes the lower density, hotter gas to rise.
When you throw water onto a heated mass to generate steam, the water turns to the vapor known as steam. This happens as the mass "conducts" the energy into the water.
No matter how hot the rocks are, the steam will NEVER heat higher than 212 F at ambient pressure. The difference in steam is as more energy enters it, the water molecules push further apart. And the further the molecules get apart, the more energy has to be extracted before they condense back out to water. This is associated with the "dew point" in the room.
A big difference in sauna quality is the temperature of the stones used to make the loyly steam. Rocks barely above 212 F don't "flash" the water to steam rapidly (resulting in less convective energy) and result in "wetter" steam that condenses out more easily (closer to its "dew point"). Superheated rocks (still needs a better definition, but likely 300 F+) flash the steam rapidly, cause the water molecules to separate further. And that requires more energy to be released from the 212 F steam before it condensates out on surfaces as 212 F water. The further apart the steam molecules are, the more thermal energy they carry to transfer into the mass of the room (including your body). But also the more widely spaced the water molecules are to slow the rate of conduction of the heat from the water molecules to your skin...
Wet steam will conduct heat into your skin faster, which isn't as Finnish Sauna "comfortable" as dry steam loyly more "gently" (or "softly" as the Finnish describe it) conducting an even higher amount of thermal energy into your skin.
A key thing people don't seem to understand about sauna heat transfer, is that convective heat flow leading to conduction of heat from the loyly into your skin, really doesn't penetrate very deeply into your body. The wavelength of the heat is different from "radiant" heat. Radiant heat is more comparative to microwaves that penetrate the mass (You may already know that microwaves cook from the inside out, whereas conductive and radiant heat cook from the outside in). Raidant heat is key to raising your core body temperature in combination with a high enough dew point in the room that prevents sweat from efficiently lowering your core body temperature.
So radiant is a KEY part of Finnish sauna too, right alongside of the convective hot air and loyly movement. But Finnish saunas (going back to the historical Savusauna design) "traditionally" use high wood mass pre-heated for pervasive but gentle radiant heat cloaking your whole body from all directions as emitted by the wood mass surrounding you. This is the good heat that the Finnish regularly describe but don't always understand the physics of.
You also feel the complexity of the conductive heat coming off the wood into your skin.
The other essential part of good Finnish sauna is the convective flow of the hot air and the loyly steam. This "moves" the hot air over your skin, and the water molecules conduct into the skin. The skin is where the heat and pain sensors are. The heat on skin is a VERY sensual experience, much more so than the radiant heat penetration into the core of the body.
I very much agree with Walker on the design of Finnish convective airflow and what Walker calls the "convective loyly pocket" above the height of the rocks. And the criticality of having the outlet vent below the top bench and far away opposite of the stove to preserve the heat and to not disrupt the convective flow. And also Walker's promotion of higher ceilings to help optimize a strong convective flow.
There should be minimal air mixing in the strata isolated below the height of the stove rocks and the convective loyly pocket above. The added air volume of a higher ceiling, therefore, doesn't really shift the volume of air you are heating for the benches where people sit. The higher ceiling also limits convective airflow disruption as people enter and leave through the door.
Walker was the one who brought this to everyone in North America's attention, including getting me to think about it, and he is spot on with these convective airflow and sauna hot room optimization observations.
3 tiers of benches with the feet positioned above the rocks on the top 2. The bottom bench being for those who need to cool down a bit, with most of their body and their feet below the rock height and out of the loyly cavity.
In my future build, I am planning to ramp from the door up into my hot room to further lower the door as compared to the convective loyly pocket, to further preserve the heat flow.
Some of those old-timers in the U.P. might be building with the same principles. We built our sauna hot room 10 foot tall after using saunas around North America.
Hello @pigstuck …I have many question but I’ll try get a answer to just this one. We are building and have the option to go 10’ instead of 8’. Why do these graphs I’m seeing show higher heat at taller ceilings. Obviously heat rises but there has to be a cut off when the returns aren’t higher temps with higher ceilings? We have the Kuma stove,and are building sooon. Hope this message finds you or anyone that cares to answer. I appreciate any input
@@raquelmillard9701 There isn't one right answer for sauna builds, but if you have a large enough footprint and can navigate steps or a few benches, I usually recommend going taller. For one, you lose less heat when you open the door. We built a 10' sauna and enjoyed it. But even 8' will still be good.
@@raquelmillard9701The key to achieving and maintaining the heat you want is the sizing of the stove for the air volume and thermal losses (e.g. windows) of your hot room. A taller room requires a stove that can heat more volume.
Over sizing is better. You can always ventilate more to bring temperatures down. But you want to be able to hit your target temperatures and you want your stove capable of overheating the rocks.
I want to build a Finnish style backyard sauna heated with a wood heater. I have read and watched lots of material so I know about the need for ventilation etc. For reasons of space, cost and heat up time etc a 5' L x 5'W will be big enough. Watching this video I now wonder what ceiling height I should have. What is your advice? thank you
My advice is 8-9 feet. - Risto
From the convective flow studies I have seen (and still need to properly gather and document), there is a minimal and somewhat disruptive (turbulent) convective flow effect on lowering the loyly cavity when stones surrounds are used on the sides of a stove.
As I conceptualize the convective airflow, the lower the heat rise starts, the more the inlet air from the vent by the stove and under the door will interact with and interfere with the strength of the convective airflow. I look forward to testing this hypothesis with hanging feathers and non-toxic colored smoke to "see" the strength and direction of the airflow. Ruspar, who I enjoy corresponding with) has posted some similar convective airflow analysis from Banya.
I just do NOT see the value of high stone mass on the sides of stoves. It likely slows radiant transfer to the wood mass in the room (thereby likely making it longer and harder to get even temperatures emitting from the wood in every corner of the room).
And such a lower convective airflow loop is likely even more prone to turbulence and disruption, than having the convective loop "up" in a proper loyly convective cavity as Walker wisely proposes will optimize sauna performance.
But if you are "stuck" with a low ceiling, then I guess any incremental improvement in the loyly convective loop will be welcome??? But at what trade off in regards to radiant heat up times for the walls and benches?
I want that enveloping, deeply penetrating radiant heat such as you get off the wood walls of an old school savusauna. I don't like saunas that only heat me "skin deep" with nothing but convective airflow and the associated loyly...
It takes much longer to transfer heat into the mass of wood with convective and conductive heat flow, than it does with radiant heat flow. Radiant heat flow efficiently penetrates deeply into the mass.
And, reiterating, this is what "I" find wrong with the modern, urban style electric Finnish saunas so prevalent today. The hot rooms are tiny, so any radiant emissions from a stove are uncomfortably too close to bathers. And the builds have comparatively little wood mass to properly and gently "radiate" heat anyway. So these modern, urban Finnish saunas eliminate the "traditional" role of raidant heat in the hot room and rely solely on convective currents. And I guess with thin wood cladding that may be all you need to heat it with as little heat as it can receive and radiate?
The marketing campaigns to drive exports have convinced even quite knowledgeable "sauna experts" that minimizing radiant heat is a good thing, when I'd say it is not... It certainly isn't "traditional" Finnish sauna design; it is a VERY modern approach.
But cheers to anyone who actually prefers the modern "skin deep" heat experience of such "modern" Finnish sauna...
What are your thoughts on some savusauna designs that are similar?
Also, if I was looking to build an authentic sauna room on a smaller scale at my home, are there any builders within the United States? For example, like cedar and stone that could be contracted for such a project? Any advice on in my research would be very appreciated. Thank you.
Absolutely svelez - depending on where you are located I would start with contractor/carpentars that could assist in a custom build or there are many ways to go about doing something yourself. You would be surprised what you can do with a nail gun and a shop saw :) Good luck in your searches.
when are you thinking of building? - Risto
Great podcast and a lot of great points raised. I realize I'm rather late to comment, but here goes.
Regarding "heavy steel sauna stoves". If you want to have a reliable stove that will last a long time, the firebox part of that stove must be heavy steel. Minimum 1/4" thick. 3/8" is even better. Now. There are ways ways that you can can shield the sauna bather from the harsh, high emissivity, of the hot steel.
- Fire brick within the firebox itself
- Using a side-mount hot water tank (also great for bathing purposes)
- wrapping the sides of the stove with "rock cages" (this is popular with IKI, and is now becoming widely adopted by Harvia, and even Kuuma)
- installed heat shields that are mounted to the stove itself (a long practice of Kuuma, and now becoming more common on Harvia)
- installing heat shields mounted to the walls of the sauna room (these can be steel, or even brick)
The main purpose is to shield the bather from the harsh radiant heat. Distance helps too, but this can be tricky to achieve in smaller rooms.
The one area of the stove that is more difficult to shield would be the door of the stove. An insulated door helps in this regard. Another solution would be exterior feed, since you can "treat" the other 3 sides with solutions listed above.
Others have pointed out that rock and even wood can radiate heat. Just at a lower emissivity, so I won't go into detail here.
Similar to Eero's opinion, we should not be overly critical, but try to educate. Branding on type of sauna as "not a sauna" or one manufacturer as "not a good stove" is not the point. We should aim to educate and instruct those on how to make the best possible sauna. How to improve the sauna they have, or the stove they have. There is never really a perfect one, since sauna design will always have some form of compromise. Oh, I wish I had unlimited budget where I could do nothing but build and play with designs. So much fun. This is why we all nerd out on design. Always chasing the "perfect" sauna. But really, the best sauna is the one you use often, in good company, and with good food.
Time for sauna.
Well said! Have you listened to our "Sauna Bullseye" episode yet?
@@theupperbench just did yesterday! I found myself nodding in agreement the whole time. 👍👍
He neglected to measure the CO2 levels in his house, which is a significant oversight. Without accurate measurements, he is relying solely on subjective feelings rather than factual data. It's worth noting that individuals working in grow rooms with CO2 levels at 1600 ppm experience no issues and function normally. In contrast, the average CO2 levels in a typical home are around 1000 ppm. Given his inability to understand and manage basic CO2 levels, it raises questions about the reliability of other information he or his website provides.
You should reach out to him! Perhaps he has taken that into account. - Risto
EVERY sauna resource/website/podcast has some blindspots and errors.
I have a Thermory barrel sauna w a Huum Hive 13 wood burning stove. I truly enjoy it, and it was a fun project for me to build. However, I don’t feel as motivated to use it as the daily temperatures go higher into the 90’s. How do you maintain your dedication to using your sauna in this climate while still managing to enjoy it as much as when it’s cooler outside? It’s just not as pleasant to me when it’s hot outside.
Try it! The very hot sauna can make a hot day feel cooler.
Are you all really inviting friends over to get naked with you in a sauna? Not sure how'd that go for me. Some of my friends are downright hairy.
It's a pretty foreign concept to Americans, but standard practice for the Finnish. We wear suits when we are in town or in mix-gendered company. - Risto
instead of criticizing barrel saunas, give tips on solving the issues
We have in later episodes.... and, fun fact, my first sauna was a barrel! - Risto
But all 3 types of heat flow optimized properly and working together is what makes good Finnish Sauna. You do WANT good, gentle radiant heat. Savusauna is filled with gentle radiant heat!!! That is as "traditional" of Finnish sauna you can get. Only modern (light weight for shipping) sauna kits ignore radiant heat in favor of focusing primarily on the "skin deep" convective heat. When in fact, radiant heat is THE heat emitted by the burning wood that is then transformed into conductive and convective heat.
Early, "traditional" stove saunas were high radiant metal stoves radiating and conducting thermal energy into stones so that the smoke could exit the hot room through a chimney instead of filling the room from the savusauna style stone hearths. This added higher radiant heat emission rates (harsher heat) from the metal... which was buffered by distance from the bather and by the rocks.
As stoves evolved to steel, they added heat shields to direct the radiant heat away from the bather, and focus the radiant into a jet of upward moving convective airflow.
Note that all stove heat (electric or wood burning) is using radiant to generate convective heat. You don't get strong convective flow without radiant heat. The key is channeling the radiant through good engineering design, NOT avoiding radiant heat. What you want is avoiding harsh radiant heat directed at the bather during use.
The Finnish commercial marketing push for easily shipped and exported light weight sheet metal stoves with low radiant heat emissions is a "modern" version of sauna that has little resemblance to "traditional" Finnish sauna from a Physics thermal energy flow analysis. Without heating a considerable wood mass surrounding the bather (which doesn't happen with thinly clad wood walls) to emit raidant heat deep into the body core, the sauna heat provided by the convective airflow is literally only "skin deep."
With such a low radiant heat sauna room, you then have to rely on humidity levels close to the dew point to keep sweat from evaporating for the core body temperature to ever rise. At that point, you are closer to a Hammam experience with steam bathing, than you are to a Finnish Dry Sauna!
So, from a physics standpoint (science) I argue that "traditional" Finnish sauna requires the high radiant heat output of a well designed heavy steel wood burning stove, that is capable of heating up the mass of the room and capable of flashing superheated steam off of superheated rocks.
The sheet metal electric stoves may produce good loyly, but they don't produce good radiant room heat from the wood surround. Yes, they provide a "modern" variation of the sauna experience well suited to bulk usage in an urban environment. But, no, they are not actually "traditional" Finnish sauna regardless of what the export marketing promotes.
Study and understand the thermal energy flow differences between truly "traditional" Finnish sauna and the "modern" sauna style Finland is exporting as "traditional" and it becomes VERY obvious the challenges associated with trying to match the amazing sauna experiences you get in Finland.
The "best" saunas all have high thermal mass of wood getting "soaked" with thermal energy for gentle, cloaking radiant heat flow into your body. That is hard to replicate with a sheet metal electric stove.
The SaunaSherpa (Kimmo) in Finland and I were discussing this on Facebook the other day. He absolutely concurred with everything I outlined in these comments.
Radiant is not only good, it is CRITICAL to proper sauna.
Banya evolved a different style of masonry shielded stove at extremely high mass for even greater radiant heat emissions. And many commercial Banya and Shvitz hot rooms are concrete or masonry walled for a different feel of the radiant than wood.
But the "traditional" Banya was a log structure, evolved from the common ancestry of Savusauna. Banya and Shvitz still throw water for steam, but don't seem to design the convective airflow so intentionally as Finnish sauna design. The Banya benches are high like many savusauna platforms above the stove were/are.
Serious question, I am looking into building a wood burning heater sauna out of a 20ft shipping container. Is this something that can be a legitimate Finnish style sauna? I am American but used to Live in Finland and became obsessed with sauna’s. Thanks for the help in advance.
Absolutely! A 20ft shipping container can indeed house a legitimate Finnish-style sauna. Make sure to ensure proper ventilation for an insulated wood lined hot room, and consider adding a changing room for comfort. Specialty container vents can easily be purchased online to help keep water and pests out. Take inspiration from Sam, one of our hosts, who converted a container into a hunting cabin using a sauna stove. Good luck with your project!
Hello upper bench thank you so much for your good work and commentary. I am new to sauna, and was wondering if any of your panel could suggest an authentic FINNISH experience somewhere in the United States that I could take a vacation to experience with my wife the proper way?I really want to experience authentic sauna as I have never done that before. Can you please suggest a location where this could be had? I currently live in Georgia, but can travel anywhere within US
Hi, Risto here. I'd be happy to recommend some authentic sauna places in North America. If you have Facebook, send me a message on our Upper Bench page... or you can email me at cjrice@gmail.com.
Had my barrel benches raised and added more rocks. Main tip after that: don't get in too early. Best experience is when the third wood portion has burned.
good advice... heating a sauna is more than just getting the air hot - Risto
And I find it VERY misguided when wood fired stove manufacturers follow that lead towards limiting radiant heat emissions with stone surrounds. It is all because most don't seem to understand the complexities of the interplay of Convective, Radiant, and even Conductive heat towards an "optimized" and "traditional" sauna experience.
The discussion in this podcast is a perfect example... Respect for your sauna expertise, but it is not thermal flow expertise from understanding the physics involved.
Which part of the podcast are you referring to?
Do you think Infrared Saunas suffer the same Carbon dioxide issues as traditional saunas. All of the Infrared saunas I see have holes in the ceiling and bottom of the sauna behind the bench. Do you believe they should use Mechanical downdraft similar to traditional electric saunas?
Hello Lukezier9616, thank you for the comment. Measuring would be the surest way to tell and vent holes probably help some. As a side note, we don't consider infrared to be a sauna because it is missing the core element of sauna... löyly!
The reason you care is because of the safety issues, best practice and enjoyment, whatever that means to each person.
I recently posted on Facebook how isolated emigrants often preserve historical cultural knowledge better than their home countries do.
Anthropologists seeking to understand historical Scottish dialects and customs go to Appalachia to study local Scottish immigrants, because their language has evolved less and their customs have been better preserved than in Scotland.
I hypothesized that the same likely happened along the banks of Lake Superior with Finnish immigrants. And descendants of the Finnish immigrants in America jumped into the thread to post examples that support this theory.
And one prime example is the Nippa, Kuuma, and Fenno stove designs. They "are" more traditional than most widely sold current Finnish stoves. And they focus on a more "traditional" sauna construction style that includes the role of radiant heat from the surrounding wood mass, just the way savusauna did and early metal stove saunas in Finland did.
This may not be politically correct amongst the sauna societies, but... In my opinion, you can get a more "traditional" Finnish sauna experience from such a Finnish-American sauna stove builder in North America than you can by importing a more "modern" style sheet metal sauna stove from Finland.
And Finnish sauna experts like the SaunaSherpa in Finland agree with that assessment. The truly GREAT Ginnish saunas he shares with guests on his tours, are not fired by "modern," urban mass-consumption sheet metal stoves. And they are not thinly clad small "closets." They mostly have powerful wood burning heavy steel stoves, and they have high thermal mass of both stones on top of the stove, and and heavy wood on the walls. And they have 3 tiers of benches with higher ceilings and feet above the stones...
"That" is great "traditional" sauna, and that is NOT what Finland is exporting as "traditional" sauna.
And it has GREATLY confused the North American Finnish Sauna market...
Old-school sauna bathing is alive and well in North America in certain areas...