What’s so funny about heat, steam, and ventilation? The Holy Trinity of good sauna

light steam graphic

You don’t have to go to Finland and partake in 50 saunas in 12 days to ask yourself: what’s so funny about heat, steam, and ventilation? Instead, you can listen to Sauna Sherpa’s Sauna Talk podcast episode, whereupon he succinctly explains the Holy Trinity of Good Sauna as heat, steam, and ventilation. Also, deep in the depths of Finland resides Lassi A. Liikkanen, author of “The Secrets Of Finnish Sauna Design” and in our podcast interview, you will also hear him lay out these three attributes to building and designing a good sauna.

Not good saunas

We sauna enthusiasts walk a tightrope. We understand that good sauna is all about heat, steam, and ventilation. Yet most of us (especially those of us here in the US) are surrounded by really bad saunas. Most egregious, there’s the Goop pretty face actress and similar fakes touting the health benefits of sauna. But she and her cronies are pushing infrared light bulb closets. Infrared is not a sauna! And the studied and reported health benefits of sauna should not be associated with an infrared cabin (which again, is NOT a sauna). For more, check out the Sauna Talk podcast with Dr. Jari Laukkanen, Principal Investigator of the seminal 2016 study on sauna health benefits.

Barrel saunas? the thermometer may read 200°f (93°c) up top, but your feet can be ice cold. There are the lame electric toaster ovens and other thin metal sauna stoves that you can pick up with one hand, and they hold about 10 sauna stones. How can these tin cans heat your body?

Bossing around a sauna enthusiast who is replacing a sauna stove with (mostly) one hand

One more bit of ranting: you can purchase a pretty lame hot tub, but it will heat water and jet it around, and you can sit in it just fine. Well, based on these deliverables, it’s probably a pretty decent hot tub. But this is not true with sauna. Just because you invest in a wood lined room, with some sort of heater that induces sweat, this does not mean that you have a pretty decent sauna.

But I know for a fact that most saunas are not created equal. Some may think that saunas heat up a room and that’s about it. However, the difference between a lame sauna and a good sauna is massive. And what sucks is that many saunas being pushed out the door in North America, well, they suck! Sorry!

What’s a sauna enthusiast to do? Snob it up or laugh it off? And, what’s so funny about heat, steam, and ventilation?

What is a good sauna?

Kimmo Raitio (Sauna Sherpa), like most Finns, is able to sum it up in a few words: “Good sauna is a matter of heat, steam, and ventilation.” These three qualifications define good sauna.

Heat

A good sauna radiating heat during a spring evening sauna session

All sauna enthusiasts know that heat is not heat. Yes, good heat is easily felt, but harder to understand. A sauna with a toaster oven heater will burn your ears, but the heat will never penetrate your body. A toaster oven heater is one of those lame “sauna heaters” that hangs on the wall, has a couple of Chinese heating elements inside, and is surrounded by about a dozen rocks. If you own such a heater, it’s ok, we will soon have an aftermarket remedy/proposal for you. As this setup is a great gateway drug to good heat.

A kick ass sauna stove makes good heat. If you cannot pick up your sauna heater with one hand we have good news: you are most likely trying to pick up a kick ass sauna heater. Why is the weight of a sauna heater important? 1) A heavy sauna heater is most likely quality built with thicker material and more heating elements. 2) Unlike a pop can, a heavy sauna heater is a lämpömassa producing machine. Thermal mass is the key contributor to good heat.

Consider the savusauna, or the thermal monstrosity ovens at public banyas like The Chicago Sweatlodge or Sky Spa. As you sit on these sauna benches, you are heating your body completely, throughout. Your body is not being heated by light bulb radiation, or hot air, but by the transfer of heat mass. That’s what you want with your own sauna. Have you ever sat on the bench in a savusauna or one of these places? As you have experienced, good heat is not “oooowwwww.” Good heat is “aaaaahhhh.”

Steam

Getting ready for steam (photo: Estonian Mobile Sauna posse).

As we ask “what’s so funny about heat, steam, and ventilation?” well, steam is the spiritual component within the Holy Trinity of good sauna. No steam? No sauna. If you are being marketed to “come to our infrared sauna” keep in mind that you will not be going to a sauna. You will be sitting in a room where light bulbs (attempt) to heat your body.

If you are at a hotel or health club and are faced with a sign: “do not throw water on the rocks” you are being manipulated by the facility’s maintenance department. In defense, many yahoo’s spit on sauna rocks, or ring out their bathing suits on the rocks, and based on these actions, you wonder why humanity has advanced at all. It’s like the guy who tried to smuggle an explosive onto an airplane in his shoes. Now we all have to take our shoes off.

But with your own sauna, you can take off more than your shoes. The holy trinity of good sauna is heat, steam, and ventilation. A good sauna has a large amount of stones that are all heated to a point of being able to produce steam. Some sauna stove manufactures stole the original idea of building a mesh cage for stones to surround the sauna heater.

By appearance, a mega stone sauna heater is one small step for good sauna, and one giant leap for lämpömassa. Conventional sauna heater manufacturers understand that stones are not costly and are a great looking cover up to the heating elements and components within. So, the accounting department steps in: “can we use three heating elements, not six?” The stove still looks like a powerhouse, but the heater is now a Chinese import and a little engine that can’t.

Tossing water on sauna rocks that don’t produce steam is about as rewarding as biting into a pretty looking apple that’s all mush.

When we make löyly, we deserve the blast of steam. In Finland, it is common courtesy to be silent when creating löyly. Come to think of it, in Finland, it is common courtesy to be silent most of the time, but if you want to get a Finn talking, ask them about the Holy Trinity of good sauna, and löyly in particular.

To the Finns, löyly is much more than just steam (and the name of a kick ass public sauna in Helsinki). Löyly is a spiritual intangible that is the soul of good sauna. Good steam is one of the three components to good sauna. When steam hits you in a good sauna, it doesn’t drive you to the door. It welcomes you, whispers in your ear, flows over your body, and envelopes you, indescribably. This is part of the magic of löyly. And once you feel good steam, you will want to create it in your own backyard.

Löyly isn’t just one of Time Magazine’s top 100 places. Löyly is something you will experience for yourself. Good steam is not “oooowwwww.” Good steam is “aaaaahhhh.”

Ventilation

A blast of löyly straight from a well ventilated sauna in Finland

When we ask “what’s so funny about heat, steam, and ventilation?” Well, ventilation is the invisible component within the Holy Trinity of good sauna.

We can sit in a $100,000 sauna, but if the hot room is not properly ventilated, you will be more apt to get a headache, feel dizzy or lightheaded. You may ask yourself why you dropped all this coin on something that doesn’t make you feel good. Here in the United States, unfortunately, bad reactions to sauna use are all too common. The cause for these bad reactions can logically trace back to poor ventilation. And this fact makes a sauna enthusiast like you and I very sad. Poor sauna ventilation is often because contractors hired to build saunas have never experienced one, let alone 50 saunas in Finland. Contractors and even DIY sauna building enthusiasts tend to be wired to insulate, envelope, and contain the heat they are creating within the four walls they are constructing.

But we come bearing good news: Installing vents is as easy as 1, 2, 3. And installing vents with “chute cover sliders” allow the sauna enthusiast infinite control over ventilation inside their sauna hot room.

Infinite Cedar sauna vent / chute cover slider
An Urban Wing sauna vent chute slider

Installing fresh air vents in order to allow our sauna to perform takes some counterintuitive thinking. Because it’s not what you think, good venting actually makes your sauna feel hotter. Much like the opposite of wind chill, air flow heat helps 180°f feel more like 200°f. More critically, air flow within our hot room interacts with the other two components of the Holy Trinity of good sauna (heat and steam). Heat and steam envelope us completely. On the bench, our feet are as engaged as our earlobes. This is fresh air thinking.

  • The sauna stove is the heart of the sauna.
  • Loyly (steam) is the spirit of the sauna.
  • Ventilation is the breath of the sauna.

It’s that simple. The holy trinity of good sauna is heat, steam, and ventilation.

Focus on these three attributes and you will be creating a really good sauna.

22 thoughts on “What’s so funny about heat, steam, and ventilation? The Holy Trinity of good sauna”

  1. “many yahoos spit on sauna rocks, or wring out their bathing suits on the rocks, and based on these actions, you wonder why humanity has advanced at all. It’s like the guy who tried to smuggle an explosive onto an airplane in his shoes. Now we all have to take our shoes off.”
    Love it!
    Glenn you should give seminars at universities that have HRM (Hotel & Restaurant Management) programs. Start the change from the next generation of hotel managers.

  2. Glenn-

    As a Finn from northern Minn, I grew up with sauna and I’m grateful. I’ve experienced plenty of good saunas and the aforementioned toaster ovens, but never devolving beyond that into infrared or anything. I finally own a sauna and it means more to me than I could have ever imagined. It’s a deeply spiritual thing and a huge source of energy for me. Sauna is health.

    I got a wood fired barrel from the UP in 03/2020. Perfect timing. The cold feet compromise is valid, but it’s so easily fixed that it’s not worth including in the same conversation as things that are not sauna. Put feet up, have someone else throw steam. My feet have never been as hot as my head, in any sauna, ever. Well, maybe laying down, but then building design doesn’t really matter. The stove is overbearing. It’s loaded with 180# of finnish vulcanite and produces the softest, deepest loyly I’ve ever experienced. This combined with the scents, whisks, cold rinse & other accessories make a great sauna. I couldn’t imagine life without my sauna.

    Someday, Glenn, a kuuma with a full structure is in order. Next house. For now, I retire to my barrel.

  3. My gym sauna is not bad sauna. A nice cedar room, good ventilation and 2 large electric heating stoves! The rocket scientist/chief engineer at the club removed the rocks nearly a year ago. Despite my consistent pleas and e-mails to mgt. no action has been taken by the club. Enter The Rock Fairy!! The Rock Fairy has access to a almost unlimited supply of good granite river rock from a landscaper. The Rock Fairy has been slowly but surely adding 2-3 rocks every day. One of the stoves is almost completely full of beautiful granite steam producing stone. There is still a sign asking not to pour water on the (formerly non existing rocks). I have taken to the opinion that sprinkling is very different from pouring. (If you say it is sprinking outside that is very different from it is pouring) The almost perfect sauna, even at a health club. It takes a little extra work but it is worth it.

  4. Right on to this, Kev! Love the punk rock/DIY action! All in the spirit of better lämpömassa.

    Andy Dufresne, Shawshank Redemption, would surely approve.

  5. Good sauna is actually a “quaternity” (as well as sometimes maybe a bit of a fraternity!) Besides good steam or löyly, good heat from thermal mass or lämpömassa, and good air induction/convection from proper ventilation, an essential in my mind is the cold water element! Ideally it would be the cold brackish water of the Baltic or the brisk icy water of Gitche Gummee or Lake Michigan. An inland lake in Minnesota, Wisconsin or Michigan in spring or fall will certainly do! In the absence of a cold lake, a backyard cow tank or outdoor shower will have to suffice.

  6. I would also add the fourth element of the cold water – but loved this article and enjoy good smack-talking wit when I read it! Preach-on, Glenn!

  7. I wholeheartedly agree. Thanks to Glenn and his book, I, with help from my wife, have built a great sauna in my backyard. Started last June in the midst of lockdowns and fully finished by the 4th of July this year. I must say I couldn’t have done without Glenn, his book and this site.

  8. Right on Ivan! Good sauna is like a candle that lights another candle. So happy for you, and your motivation and dedication towards creating your own authentic sauna health and wellness backyard retreat.

  9. Hi Glenn, thanks to your book I have a beautiful sauna in my backyard shed in Ontario with a Finnish heater. I have a question about steam/loyly. Should I be using cold, hot or room temperature water in my bucket with the ladle. Does it make a difference?

    Cheers!

  10. Love your question, Eric! I prefer warm water on the sauna rocks as it blasts the steam a bit more, and doesn’t tax the rocks as much. That’s been my experience, and open to other thoughts. This does remind me of the question of which way to stack firewood: bark up or down, as there are strong opinions both ways.

  11. Hi there,
    Older woman here asked to build sauna for daughter. Lots of experience in high grade construction, wooden boat/ architectural repair etc but zero with suanas. Does you ebook cover all construction details for building a sauna that will last a few deacdes in the northeast …including pad/ foundation options ?

    And…since building from scratch would like to make it charming and functional,
    are there lots of inspiring pics in the ebook ?

    Thank you

  12. Mary:

    The book should help you with your project in several areas. Not so much on the inspiring tips, i suggest firing up the googlator for good photos of other saunas or even better, please scroll through guest posts on this website.

  13. I built my sauna in spring and been using it every week. Now it’s winter and the floor is always cold. Need help figuring out how to ve t it better?

  14. Hi Glenn!
    Here’s my question for the community about venting:
    I have a wood-burning Kuuma stove, with an intake vent just behind it at floor height.
    On the opposite wall, (where the seats are), I plan to place adjustable outflow vents about two feet higher than the stove, and more adjustable vents above those lower vents at about 12” from the ceiling.
    (This is an outdoors sauna, venting to the outdoors and I do not want to use any electrical fans).

    After reading everything I could find on the subject, this seems like proper placement,
    I wonder though, if the upper vents should be higher… or lower than 12” from the ceiling?

    Some people advise vents in the ceiling, but that seems like a way to suck out too much heat before the lower bench gets hot enough.
    Others advise very low vents with no high vents, but I’m unsure if having only lower vents will have enough pull to get the stale air out of the ceiling area.

    With these thoughts in mind, I plan upper and lower vents – all above the sauna stove rock level, where heat and pressure are highest.

    Okay, now, my question:
    At 12” from the ceiling, the upper vents are just behind my head when seated… is that good?
    OR, would I want the vents a bit lower to get air flow lower down my body?
    OR, should they be higher than my head for some reason?

    It’s mostly guesswork, I’m sure, but maybe someone has some experience with this?
    Thank you!

  15. Ken,

    I spent a week in Finland recently, and during my visits to some top saunas, I had a keen eye towards ventilation. In my case, the adage “the more you know, the less you know” applies to ventilation.

    As a general rule, I like a gap along the hot room door, and an intake vent down low, then at least one vent about 1′ from the ceiling. All with “chutes” so we can open and close (most always open down below, and pretty much always open above).

    I come back to the spiritual side of sauna. And in this case, fire up the Kuuma, sit on the bench, toss some water on the rocks, and feel it.

    We can look at CAD drawings and layouts and read the dogma about ventilation, but it comes back to that moment on the bench, as we listen to the soul of our sauna who will gently whisper in your ear and tell you where it wants to breathe.

  16. Thanks Glenn,
    What I think I am going to try is several out-flowing vents up high – (close to the ceiling as you suggest) and several out-flowing vents lower down at seat level too.
    Since they can all be adjusted as needed, (or closed completely), the more vents the better.
    The incoming, 15”x7”, air vent is on the opposite wall at floor level – behind the stove.

    Additionally, I want to try running a “chimney”, (using rain gutter), that connects each lower vent to the one above it… these chimneys would be open near the cool ground and open above the roofline… painted black on top, white on the bottom…
    … Back inside the sauna – if I open the top vents a small amount, the naturally occurring high pressure up near the sauna ceiling will push air out the vents and up the chimney creating a “draw” up that chimney… the lower vents could then be open wider than the upper vents… hopefully all of this will create a situation where the hot, steamy air is pulled down and around the people sitting on the benches, before being drawn out the lower vents.

  17. I’ve been enjoying our backyard sauna now for three months and just this past week got around to putting on the siding. I left the back wall for last because this is where I knew the upper vent would be cut through. I knew this was where because I’d stared at the same spot on the inside of the hot room sauna after sauna getting up the nerve to blast a hole through this lovely wall I had built. With siding taking up precious room in my garage I couldn’t put it off so I cut through the T&G, the foil bubble, ALMOST the left speaker wiring!, and the Roxsul. I set four screws from the inside to the outside so I could cut the corresponding rectangle out of the building paper and exterior sheathing and lo and behold I had a gaping hole in my hot room wall. I cut in a 6″ wide X 4″tall vent, boxed in with framing and trimmed out with a cedar slider inside and a louvered cedar cover outside. During the same fit of hacking at the hot room I pulled the pins from the heavy-as-heck sauna door, set it on the sawhorses outside and opened the bottom gap up from 1″ previously to a full 3″.
    Prior to the added ventilation I found maximum comfort at about 180 degrees on the top bench. I’d take four rounds; one dry, one mostly dry with maybe two stone soakings near the last 7 minutes. The third round was a stone soaking every 3 minutes and then a fourth finnish round dry again and usually with just coals left in the stove. Here’s the thing. Through all of this I used MAYBE 1/3 of the bucket of water and more often than not would have to “tap out” with a few minutes left on the sand timer because I was getting dizzy or uncomfortable. The steam (I now realize) was stifling and lingered for what felt like a painful forever.
    This weekend with the added ventilation I was feeling fabulous at 190-195, used up 2/3 of the bucket and not once felt stifled by the steam. It washed over me, teased it’s way into me while I breathed and then slowly and quietly subsided until it was time for another splash, never once making me feel uncomfortable as it did before the venting change. I believe for the first time ever I experienced lämpömassa? I was shocked round after round to open my eyes and see the sand timer had run out completely while I relaxed. I used to shoot daggers at the sand timer willing it to drain down faster so I could get out with my pride (but the sand timer never gave in to my psychokinesis).

  18. Right on, Kelly. Explaining good heat, steam, and ventilation is like trying to explain an awesome sunset out in nature. But you’ve done a nice job of it.

  19. Glenn, I believe you’re right about listening to the sauna and that it will “whisper” where to place the vent.
    It makes sense to me that my intuition is far ahead of my logical reasoning… I like that way of doing things – it’s often best.
    But intuition like that is built on experience.
    I’m just a newbie, you’ve taken thousands of saunas and are way ahead of me.

    So, I’ve been reasoning it out… and “feeling” what to do.
    At first, I was going to place chimneys on the vents to encourage “draft”, but decided that maybe a vent chimney would never get hot enough to draft, so I skipped it.

    Everyone recommended lots of ventilation, so I decided that if the vents were adjustable, I couldn’t have too many – (I could always close some of them).
    I placed four, 4” vents, 6” from the ceiling, opposite from the stove, above the top bench… these are barely opened during use, just enough to encourage the oxygen flow and to control the temp a bit.
    Four more 4” vents are lower down, 2” above the top bench… these are used to pull the loyly downwards, around anyone sitting there.
    I would have also placed vents below the top bench, but since the design of my sauna isn’t good for that, I have yet to add those – (I hope to do that in the future).

    With these eight vents, (and the great Kuuma wood burning stove, you recommended), I’ve found it easy to control the temperature and how long the loyly lingers.
    The lower vents help the loyly to nicely envelope top benchers, it hits our face first, then washes over us and down our backs, then around our knees. Our feet are above the rocks and hot, but the loyly is barely felt below our knees – maybe some future lower vents can remedy that.

    The oxygen level feels fine – I’m new to this, I only know what I know – but it feels good to me.

    Thanks again Glenn for your excellent blog/advice and for gathering this community – always very helpful!
    Ken

  20. I’m sure this is not new to the sauna community, but it’s new to me – I made a wooden hand-fan, (like a large ping-pong paddle), with rope wrapped handle to make it easy to hold.
    If our session is extra hot and the loyly is also extra hot, that can be good…
    but sometimes, this hand fan can soften the blow a bit and redirect the loyly, slightly away from our faces and down, towards our legs.
    Later in the night, when the sauna is cooling down, the fan is excellent for pulling loyly from above our heads, down onto our bodies.
    It takes very little effort – less than using a towel, since it’s one handed.
    If done thoughtfully, gently, it’s very meditative.
    It’s good to change things up a bit now and then.

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