Please welcome back Billy to Saunatimes. You may remember Billy from when he shared interest in the care and storage of vihtas. Recently, Billy has recently become interested in sauna thermometers. He has a recommendation for us. Let’s check in with Billy from his hand build sauna in the hills of North Carolina. Hi Billy!
Lord Almighty
– Burning Love, Elvis Presley
Feel my temperature rising
You may want a sauna thermometer. Frankly, in my opinion, you may need a sauna thermometer. Here’s my story about sauna temperatures and sauna thermometers. Hope it helps you. First, keep in mind that there are generally three different types of thermometers:
DIAL (or Spring) Sauna Thermometer
A dial thermometer uses a coiled piece of metal that is sensitive to heat. One end of the spring is attached to the pointer and as temperature increases, the metal expands and the pointer moves higher. As temperature decreases, the metal contracts and the pointer moves lower.
Tube (Bulb or Liquid) Thermometer
In a tube thermometer, the liquid expands as it is heated and contracts when it is cooled, rising and falling with the temperature.
Digital Sauna Thermometer
The measurement of the temperature is made by a computer “thingy” that reads the temperature of the probe and displays the temperature digitally.
My story about thermometers and sauna temperature:
In June, 2021, I completed construction of my wood-fired sauna. As part of outfitting my new sauna, I purchased a DIAL sauna thermometer. (I won’t mention the sauna brand, but it’s an old one.) I calibrated it before hanging it in the sauna. I had only experienced wood-fired saunas on a couple of occasions, and many years ago, so I was inexperienced as to how hot it ought to feel. However, I had reliable information that 180° F was a good temperature.
So, for the past ten months or so I’ve been using the sauna. Family, friends, and guests have enjoyed it, too. None of us are experienced sauna folks. My DIAL sauna thermometer (which I calibrated myself) seemed to work and we usually kept the temperature right at 180° F. The temperature in the sauna seemed really, really hot to others and to me. But, the thermometer always read about 180° F, so we figured it was just us: that we weren’t in “sauna shape.”
A few months ago I began to research sauna thermometers. Specifically, I was zeroed in on accuracy: not aesthetics or readability. That was a long investigation that has included communication with American and European companies, and reading lots of specifications and lots of reviews. Essentially, everything I read and heard convinced me that none of the thermometers were particularly accurate, and that’s all I really wanted: accuracy.
Then, I investigated and consulted with scientific (not sauna) companies and one recommended a digital thermometer that they carried. I ordered it. But, alas, the DIGITAL readout (the numbers) became unreadable as the heat rose. So, that didn’t work either.
I worked, then, with another scientific company, and a fabulous rep, and we zeroed in on a TUBE (bulb or liquid) thermometer, certified to be accurate within 2° F. I ordered it and placed it in the sauna. Here’s the company and model that I selected:
Cole-Parmer
Item # 08008-42
Easy Read Thermometer
0-300 Degrees F
The good news? It seems to be working great!
The bad news? This new TUBE (bulb or liquid) thermometer indicates that my DIAL sauna thermometer was low by at 20° or more! So, from the beginning, I think my sauna has been rocking at 200° or more. No wonder we’ve felt so hot.
So, I now have had a few sessions with the new TUBE (bulb or liquid) thermometer. I’ve found that I like the temperature to be aout 175° F. I can also control and maintain the temperature (adjusting the stove) by watching the thermometer. It’s been a much more pleasant experience in many ways. Because the new TUBE thermometer was harder to read, I created a chart to put under it. A couple of photos are attached.
Here are the take-aways, in my opinion:
- I calibrated my DIAL thermometer before hanging it and it was still wildly inaccurate.
- If you want accuracy, then I strongly recommend a TUBE (bulb or liquid) thermometer from a scientific company. Mine was a bit hard to read, so I made a chart to hang behind it. Now I can read it without my reading glasses and even from a few feet away.
- Now I know what 180° F feels like. Before I didn’t and we’ve been using the sauna way too hot because of an unreliable, inaccurate thermometer.
So, with apologies to The King, now we are feeling our temperatures rising with love (not suffering). Speaking for myself, and truly, now I’m just a hunk, a hunk of burning love.
7 thoughts on “Sauna thermometers: Just a Hunk, a Hunk of Burning Love”
Awesome thanks! I’ve been looking for a thermometer that works and not crazy expensive. How did you mount it?
A few thoughts…
– Tube thermometers are generally considered a bad idea in a sauna. They do break occasionally and when they do it is nearly impossible to get all of the shards of glass out of the soft wood of a sauna (also not fun on naked bodies). This is why in saunas in Europe you almost always see a less accurate analog dial.
– Digital thermometers with remote sensors are the most accurate option. The electronics/readout can be placed lower where temps are cooler and the sensor at an appropriate height.
– Placement is critical to accuracy. Temps in a sauna vary a considerable amount. The closest thing to ‘official’ is on the wall 1m (39″) above the middle of the longest bench opposite the heater.
I’ve been using a candy thermometer that someone gave me as a gift and I’ve never used for its intended purpose. It seems to work quite well and the “soft ball” and “hard crack” jokes never get old.
Any follow up on – to Keith’s question – the best way to mount it?
@Meg
I too use a candy thermometer, I made a little support and it’s very precise!
No liquid in there, the metal pipe is the “sensor”.
I also have a dial one, wall mounted, and at low temps it’s not precise at all but at 180°F it’s right on! 😉
Keith,
Use a piece of a board a little longer than the thermometer. Put a hook or brad in the top and hang it. (There’s a hanger-thing attached to the top of the thermometer. Hang the board (at a recommended height) and you’re done.
Then, if you wish, make a chart to glue/fasten to the board underneath the thermometer with the readings shown beside the thermometer. My chart ranges from 150 to 220. (You will have to lay thermometer down on the drafts of your chart to make sure your chart lines match the thermometer lines.)
Billy
I have a tradition sauna thermometer inside my woodfire sauna here on Lasqueti Island, British Columbia, but I’m a bit of a precision geek when it comes to my sauna and I don’t like opening the sauna door to check the thermometer or guessing based on time since the fire has an attitude of its own. While on holiday in Europe, I stumbled on to a reference to Ruuvi temperature sensors and their use in saunas. I purchased the RuuviTag Pro (2 in 1) per their recommendation and am thrilled with it. Now I tend my fire while sitting outside, sipping tea and watch the temperature rise via Bluetooth connection on my phone with the Ruuvi app. I know exactly when I hit the sweet spot!