Sauna Build - Wood Boiler Heated?

[Chris1017]

I have been wanting to build a sauna since my wife and I originally built our house almost 20 years ago. The original plan was to have it in our basement, but things changed over time and that became our canning closet. Moving forward, I would much rather have an outdoor sauna and I believe that now is the time to either **** or get off the pot so to speak. So, the question is can I heat it with my outdoor wood boiler? I have looked around and am not seeing to many ideas on doing such. Any help and/or thoughts is much appreciated!

Chris

 

[bassJAM]

With a heat exchanger I don't see why it wouldn't work.

 

[DennisK59]

Sauna's use hot dry heat, I don't think a boiler will get that hot enough safely.

 

[finn]

No, I don’t think so.

Saunas typically are heated to temperatures of 175-195 degrees F. I can’t see a wood boiler being able to deliver that much heat to the sauna hot room without using pressurized steam. There likely isn’t enough delta T between the boiler water temperature, which is probably in the neighborhood of, I’m guessing 160 degrees max and the desired room temperature, let alone getting the rocks hot enough to flash a good “loyly” when you splash water on them.

There are a couple of Facebook sauna construction and user groups, but expect to hear a lot of “my way or the highway” rules from the sauna police on them.

 

[Chris1017]

Thanks everyone for the replies. My current Central Boiler 5036 will go up to a water temperature setpoint of 195, which means once the dampener actually closes it is around 200 deg. I. currently have a heat exchanger that is about 2" in diameter and 4' long. When cold water isn't going the reverse way through it, you are physically unable to touch it because it is so hot. My thought process was if there was a steel box that was 16" x 16" that water circulated through, with rocks on top, would that be sufficient?

 

[billconner]

The rocks need to be hot enough to make steam when you sash water on them, so more than 200. I lived in northern Sweden for a year and tried a lot of saunas. Everybody had at least one. 220 was not unusual. I liked the wood burning stoves, most repurposed stoves with welded on steel to hold rocks. Very nice if adjacent to a pond or lake to plunge into after.

 

[finn]

In order for water to flash to steam instantly when a ladle full is splashed on the rocks, the rocks have to be well above 212 degrees to transfer the energy to efficiently complete the phase transformation from liquid to vapor.

On the other hand, you could have a nice warm room of maybe 170 degrees with your plan.

Just wouldn’t be a full sauna without the loyly

 

[fitter30]

Sauna's use hot dry heat, I don't think a boiler will get that hot enough safely

What water temp r u running? Max water temp for your boiler? What r your heat emitters in the house? Sauna room temp have a big range just looking at a couple sites. What temp are thinking?

 

[Jon h]

Short answer. No.
Use a proper stove. Don’t go electric either. They don’t get nearly hot enough. All the electric ones I’ve been in only get to between 80-90c (176-194F). There may be ones that will get a room hotter. But electric is better than nothing and a new person that doesn’t have a lot of sauna experience will think it’s hot. But a well seasoned sauna person will prefer 100c and up (212-248f) I grew up with both electric and wood. I currently have a wood one and it’s great.

Regards,

Jon Hamalainen

 

[Jackfre]

I used to build wood fired saunas. Can you weld? 1-30 or 36” section of 12” Sch 40 blk pipe. 1-30” section. Fishmount the 30” to the back of the 36. Put legs on the 36”. On the vert section weld a 3/4” loop so it projects into the bottom of the horiz 36” piece. It should set vertically. Use a 3/4” return bend for spacing. You build the fire around this pipe. Set that vertical in the firebox. Tricky part is making a door but if you can do the first part you can do the second. Cut your 6” smoke pipe hole in the top of the fire box. Get some galv sheet metal and make a tapered box to mount onto the fire box and fill it with your rock. Fill the back vertical pipe with water and put a sheet metal cap on it. It should fit loosely. Don’t build a bomb. Build a fire and in no time you water in the tank will be boiling the space will be hot as hell with a good dry heat. With the hot water get a sauce pan and when you want a bit of steam scoop it out and pour it on the rock. You will get great steam out of this too. I’ve built a couple dozen of these, all at least 40 yrs ago. Everyone loved them.

 

[couch67]

Good on you to finally build a sauna! I agree with the replies - the boiler simply wont be able to get the sauna to a 'useable' temperature to enjoy. There's nothing worse than a luke-warm sauna!

A simple wood fired sauna stove would be the way to go. There are also a few sauna builds on this site, @35k0 did a nice build...

 

[Fav Onefour]

Finnish Sauna?
I see those things around with a little plume coming out the stack. Granted, it's not a boiler, but it's a sauna and it's wood burning.

 

[Chris1017]

Thank you everyone for the latest replies. I guess I was just trying to capitalize on the heat I already have instead of purchasing another source. Hopefully, I will be updating this thread soon to a sauna build thread.