An official definition

I’ve briefly described what sauna is, but don’t take my word for it. I’m just some random guy on the internet. To arrive at an official definition, you must consult the Finnish sauna organizations. Sauna is their cultural heritage after all. The oldest and most prestigious of these societies is the Suomen Saunaseura ry (Finnish Sauna Society). One of the principle founders of the society, H.J. Viherjuuri, describes sauna, in his book Sauna: The Finnish Bath, as:

“a one-room hut built of logs, with a large rudimentary stove upon which stones are piled. Steps lead up to a slatted wooden platform along one side of the room, and here naked bathers sit or lie in the hot air under the roof. The stones are heated until they become red hot, causing temperatures as high as 280 degrees Fahrenheit; the ideal temperature is between 190 and 200 degrees F. During the bath, water is thrown on the stones, but the air remains dry because moisture is absorbed by the wooden walls instantly.” “After perspiration, the traditional sauna in Finland includes beating with leafy birch branches, washing, and a plunge in the nearby lake or a roll in the snow outside.”

The current President of the International Sauna Association (ISA), Risto Elomaa (who is also on the board of the Finnish Sauna Society), defines sauna as,

“a room with walls preferably made of wood. The key thing is the stove with sufficient stones that are heated either with wood, electricity, gas, etc. Heating can be continuous or one time. The temperature measured at the level of the shoulders is 70–105° C (160–220° F). The humidity is controlled by throwing water onto the stones.” “We … propose cooling in between. You can do that with cold water, jumping into water even ice hole or just sitting outside.”

And the North American Sauna Society’s (NASS) Eero Kilpi describes sauna as, “a closed space with a heater that has rocks on it. Anything that doesn’t have a heater with rocks on top is not a sauna.” NASS recently made this explainer video to help American’s understand that sauna is a much richer experience than what they’ve been exposed to at hotels and gyms.

As you can see from those definitions, there are some common elements that make a sauna. These elements are: extreme heat (+160°F), the ability to bathe, heated rocks, löyly (steam), multi-round process of alternating heating and cooling (the cool-down is as important as the heat). Michael Nordskog in his book, The Opposite of Cold, boils it down to, “implacable dry heat interrupted by waves of löyly.”

These are the authoritative voices for defining sauna, not a company, salesperson, or some doctor on the internet. They even supersede the dictionary…unless, of course, it’s a Finnish dictionary.

Sauna scorecard: infrared and others

Now that we’ve established an official definition of sauna, let’s circle back and assess some things that are commonly called “sauna” to see how they measure up. I’ve created this handy-dandy scorecard to assist with the task.