Thanks for your well-educated comment, Donal! It’s interesting to hear from someone living in Ireland where I didn’t stumble on any saunas myself. (There was a time when I lived and worked in Cork, Ireland. I’ve never seen more gray brick walls and dog poop on the streets than I did there. But the greenery was beautiful!)

How nice to come across someone so invested in Finnish sauna tourism that you visited a different sauna every day during your stay. I’m also happy to hear about your own sauna, and that clear improvements have happened with roofing since 2009.

I’m actually very glad you brought up this temperature issue. What you’re describing comes down to specific public saunas vs. most home saunas. Since the absolute majority (95% +) of saunas in Finland are home/private saunas, the conditions in them are far from the best (and few) public saunas. For instance, the sauna stove in Kotiharjun sauna has 1,500 kilos (!) of sauna rocks, and it takes a cubic meter of firewood and about five hours to heat it. The sauna is famous for its soft löyly despite the harsh heat, which is achieved by that gigantic rock mass and the sauna room itself being so large. (Löyly can actually feel much more intense and sting your skin in a 2–3 person sauna that has about 80 C.) Also, in the men’s sauna specifically, the highest bench was added later and meant for those who want extreme heat.

Similarly, Rauhaniemi offers a large and a smaller sauna, the latter being less hot. The few public, wood-burning saunas that have a heat-storing sauna stove (kertalämmitteinen kiuas in Finnish) and that take hours and a ton of wood to heat, practically can’t avoid getting super hot because the temperature is difficult to control. Rajaportti, too, has a heat-storing sauna stove that requires meter-long logs every half hour, for six hours straight. Since wood isn’t added after this (unlike in most wood-burning home saunas), the stove reaches its maximum heat that it then keeps releasing for hours, until it inevitably starts to cool down. This also means you probably don’t sit in 115 C just before closing time, as that would be very poor planning on the business owner’s side.

In short, the fact that the temperature can be as high as 115 C doesn’t mean it’s what it should be, has to be, or that it would be the best temp.

Also, you’ve managed to pick (probably not by accident) the few, most famous, and hottest public saunas that Finland has to offer. What I mean is that most public saunas are far less hot. Had you tried some other, still fairly famous public saunas, in Kuusijärvi or Sipoo, for example, you would’ve experienced much less intense heat. I personally rarely go to public saunas, having several of my own, but I visited Hämeenlinna in spring 2025 and tried three saunas there, all having less or around 80 C. The biggest of them (electrically heated) was still intense since the feeling of hotness and löyly doesn’t fade away like it does in much smaller saunas.

Home saunas, on the other hand, are perfectly ready when they hit around 70 C. That’s when everybody knows it’s a good idea to enter the sauna; starting with less than that wouldn’t be ideal, but when you start with 70 C, the temperature can afford to get higher, which will happen if you’re adding wood (or the electric sauna heater is kept on). Hitting 80 C is still totally fine, but if the temp gets higher than 85 C, that’s just unnecessarily high, which almost everybody knows and agrees on (people themselves, sauna manufacturers, and health sources). It’s not that 85 C + is too much to bear, but it just doesn’t give you any added benefit. It only costs you more in fuel.

Finns know that if you truly prefer a hotter sauna environment, it can be achieved with more löyly pouring, not by increasing the temperature, which isn’t wise and only makes the air drier and makes it more difficult to breathe. For a truly hot sauna, as long as you keep the stones hot and have a max. of 80–85 C, you can keep pouring water, and get intense heat and löyly for as long as you like. This is always true if your sauna heater is big and effective enough. It may be that some of the people who think 85 C isn’t enough, don’t have a sauna heater that allows them to pour enough löyly to bring that intense heat they’re after. With an amazing sauna stove, such as IKI, you can actually have the temperature surprisingly low (50–60 C) and still enjoy intense heat and löyly that feel everlasting. That can’t be achieved with almost any other commercially available heater. It’s this exact principle (temp vs. löyly for heat) that so many people, especially in North America, don’t get.

There, of course, are few Finns that actually enjoy extreme heat (both in temperature and plenty of löyly pouring), but they certainly are a small minority. Usually they’re men, many of whom have bigger bodies (not because of muscle but mainly fat), which means they also have more “padding,” allowing them to tolerate extreme heat better.

Finally, the decades-long Finnish sauna studies (by Laukkanen & Laukkanen) with thousands of participants show that people sauna in slightly less than 80 C. That’s also the temperature where all the health benefits were achieved, not in 115 C!

All in all, it simply wouldn’t be accurate for me to say that the ideal or best sauna temperature is 115 C when the reality is so different. The experiences that saunas like Kotiharju and Rajaportti offer are very unique and special, and for many, they would lose their appeal if they suddenly became “normal” saunas. Like any attractions, they have to offer that something little extra.

I’m glad you’ve been happy with your Kastor stove (it really is a good brand) and hope you haven’t required 115 C from it! 😅

My background: Barrel sauna in my garden since 2009, made of red cedar and lasting very well. My heater is a Kastor wood-burning stove and thanks to your article, I now know its made by Helo! As you say in your article on barrel saunas, it heats up very effectively. I use a bucket shower to cool down between sessions. All barrel saunas sold here (Ireland) now come with a shingle roof. Back in 2009, no roof cover was supplied so I use a light tarpaulin.