What would you choose for heating a sauna?
Looking at building an outdoor sauna. I like the idea of switching a switch and be ready in 10 minutes. Friends are saying to use a potbelly stove and wood feed it from outside. Have an endless supply of wood scraps.
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Replies
How easy is it to get precise temperature control if you go wood fired? And who's to say you will want to stoke a fire an hour or two before you step in? It's a luxury item and I'd go for convenience.
Wood is traditional but troublesome. Electric is quick, easy but not very romantic.
IMHO electric units get used more often. Saunas can be great for when your sick, just feeling down or a bit stiff. Exactly the sort of times when your not in the mood to fiddle with wood. Flip the switch and in a couple of minutes your ready to get some relief. Your far more likely to use an electric fired sauna frequently.
On the other hand preparing and stoking a fire to work the sauna is part of an elaborate mating dance and the ladies really dig the preparation on their behalf. If you can mange it the sauna - snow thing is great. In many ways more invigorating than the hot tub route. On an individual level I can see where the minor procedures necessary for the wood unit could be established as a relaxing ritual but you would need to be that sort of person.
Wood or electric. Yes is the ideal answer. Having both would leave the options open for maximum enjoyment.
If I had to chose only one I would go with the electric. Saunas are great but they are little more than bragging points and a line on a real estate ad if they are not used. Most saunas, hot tubs, whirlpool baths and decks go unused. After a few uses to justify their existence they typically go unused for years. Money wasted and opportunities lost.
Edited for clarity.
Edited 12/21/2005 9:53 pm ET by 4Lorn1
Having grown up in far northern Michigan in a Finnish family, I've gotta take up for wood. All the electric saunas I've been in suffer from a common fault - too little heat. Sure they warm up fast, but one splash of water and they cool off fast. Grandpa's barrel stove with 20-gallon saddlebag water tanks and 3 cubic feet of fieldstone on top not only got the room up to 140 degrees, but it kept throwing steam as long as we'd pour water on it. Granted, it took an hour to get up to temp. Life is complicated.
Re: "- too little heat."I suspect this has to do with the electric units installed being too small. Go for the higher wattage units if you have a chance and it may largely correct this common deficiency. I once installed a dedicated 100A circuit. Plenty of steam as hot as you want it. I think it was overkill but you make a point I have heard before about weak electric units. Some sauna designers and manufacturers are trying to make installation as simple as possible and scrimping on the steam units they specify.
Go for the wood Buy a real sauna stove and have at it. Ours gets fired at least once aweek for the last eight years .
I heat my outdoor sauna with wood. I'm in MN and on days where the temp hovers at or below zero, it takes a long time (hours) to get the thing hot (180-200 deg F). I burn dry oak, with a 7x8x7 steam room, and the building is insulated, except for the floor. I have to haul water (for washing up and throwing on the rocks) to the sauna in 5 gallon pails every time I use it in the winter because ordinarily there is no heat in the place. Some day I hope to rig up an yard hydrant that comes up through the floor in the steam room. There's a water tank on the side of the stove for providing hot water. I personally prefer wood over electric, so I'm OK with dealing with all this.
If you are looking for convenience, don't even consider wood. In any case, unless you'll be keeping the building warm all the time, don't forget to consider how to keep the water you'll need out there from freezing when you're not actually using the sauna.
Brent
I'm also in MN.
Not sure if I'm into a ritual for stockin the thing like 4lorn1 suggested. Sounds more like putting on the Sorels and walking thru the snow bank to the wood pile. As far as impressing the Ladies, well DW thinks it's a waste of my time... More looking for a project that my son and I can build together, and if in eye sight of the back windows of the house I'm sure it has to look good.
Kinda like the idea of both wood and electric.
How do you control the combustion air for the stove? Want it as air tight as possible but don't want Carbon Monoxide issues. What are you using for insulation? I don't mind caring water from the house.
My sauna is a 10x12 shed on treated skids, with a 8x12 lean-to for firewood on one side. The stove in the steam room has a firebox that opens to the outside of the building, under the lean-to. This keeps all the wood mess and smoke outside where it belongs. The stove is a worn out homemade thing that I got for free; it's not made how I would design it, but the price was right. I'm going to make a new one when this one dies, and the new one will be a better design that will heat both the room and water more efficiently. The firebox is definitely not air tight; it's got a cast iron door with a horizontally sliding damper just below the door. I've never had a problem with carbon monoxide or smoke with this stove, even if I leave the firebox door open a crack.There's two rooms, a dressing room and steam room. All walls and ceiling are all 2x4 construction, 16" on center, plain old fiberglass insulation--what's that, R11 or something like that. The floor is wooden, 2x10 joists; the steam room is sloped to one side, where the water falls into a rain gutter built into the floor and channeled outside. The floor is covered with rubber roofing material, made for the flat roofs of commercial buildings. Also, the vapor barrier is plain old plastic everywhere except for the steam room, where it's aluminum foil. I heard the plastic doesn't last long with the high temps.It's not super fancy, but I could post a few pics if you're interested.Brent
Thanks for the note on the vapor barrier. I didn't know about the poly breaking down with the heat. One thought was polystyrene insulation. I could use the foil-faced style. I was thinking of making the walls in sections that could be dissembled, if or when I move again, I can bring it along. I have 400 sq' of 1X6 cedar TG from a demo and was thinking of making the walls on 2X2's 1.5" styrene (R~13) and 1X interior and ext. TG. With the weather cold I could build some of it inside and join the sections together when done.
Like the idea about the gutter system on the floor. Don't want it icing up when not used. What is the rock layout for the steam?
I'd be intereted in some Pix's if it's not too much trouble.
Thanks again
Edited 12/22/2005 7:08 pm ET by hammer
Here's some pics of my sauna.The lean-to for wood storage was added a year after the sauna was built--got tired of digging for wood under a tarp and snow.The outside is 3/8" cedar plywood with cedar battens and trim. The windows are storm windows. The interior was finished with some T&G pine boards I pulled out of a house before it got demo'd. I used this in the steam room, too, but it's not ideal (however, again, the price was right). Even after sitting unfinished drying on a living room ceiling for 15 years, the pine leaks sap when the sauna's heated. I ran out before covering all the walls, so I finished the rest (two opposing walls in the dressing room) with salvaged pallet boards. The benches are clear cedar and are removable for cleaning. The steam room door I made from oak planks milled from trees off my property; these particular planks weren't any good for anything else, but they made a decent door. The outside door is an insulated metal door I got off the scratch-and-dent shelf for $3.Kind of hard to see detail about the rain gutter drain in the pictures, but basically, I fastened the gutter to the side of a floor joist and ran the sloped floor over it. Both ends of the gutter slope to the middle and empties into 2" PVC pipe, which goes underneath the wood pile and out the back, down the hill. No trap. It's never frozen up on me (however, I have had the occasional mouse run up the pipe and try make themselves at home--should put some wire mesh over the opening).As I mentioned before, the stove was a freebie. Works OK, but doesn't heat water as fast as I'd like. Part of the firebox extends into the water tank, but there's not a lot of area for heat transfer. The next stove will sit lower to the floor, will have a slightly bigger firebox, and will hold many more rocks (got them off a farmer's rock pile). I'll also do the hot water heating differently, probably wrap a coil of copper tubing around the firebox and run both ends to different heights on a water tank mounted somewhere above the stove.I heat the steam room to about 200 degrees; at that temp, you get good steam off the rocks and there's plenty of hot water.In the summer time, I run a hose to pipe I've got rigged on the back outside wall of the sauna. This pipe has a valve on the inside. In the winter, I can't use the hose anymore, so I haul water in 5 gallon pails. I load 4 pails in a sled, fill them up at an outside hose bib at the house and pull them to the sauna. Two trips usually is enough.If I was to build another outdoor sauna, I'd pour a concrete pad for it and heat the floor (in addition to the wood stove). I also wouldn't bother making any kind of storage area above the sauna.Brent
That, sir, is a thing of joy.
Brent,
Awesome job!!! This is more than I will probably take on but thanks for the Pics.
Really appreciate the details with the firebox, rocks and exterior wood access.
Now that the holiday's are coming to an end looks like I'll schedule some time to get started on this.
Thanks again for the ideas and advice.
Hammer,
I woke up Christmas morning to the sound of neighbors banging on my door, my son shaking me, saying, "Dad, I think you better get up," and a bright orange glow in my bedroom window. It was my wood-fire sauna, totally ablaze, which had been used by friends about 5 hours earlier.
For what it's worth, here are the details:
It was built about 25 years ago as a birthday present for my wife. It was wood framed, insulated, with cedar siding inside and out. The wood stove, which I'd built myself had 3' clearance to walls and a Metalbestos brand insulated chinmey that extended about 4' below the ceiling. I say this because as a former home inspector, I'm pretty familiar with all the code clearance requirements. The chimney was installed using the hanging brackets furnished with the chimney. They allow the pipe to be about 3 inches from the rafters or blocking that supports the chimney. Metalbestos recommends 2".
All bets are off when the stove is used in a sauna. In a house (I heated my house with only a woodstove for 16 years), there is seldom, if ever, a need to build a really hot fire other than for short periods to keep creosote from building up in the chimney. But in a sauna, the usual practice seems to be to stoke the hottest fire one can so you can hop in sooner. That's what happened the night before my fire.
The friend who stoked the fire, lit it and came back in the house. The first person in the sauna an hour later reported that the uninsulated pipe was glowing red. They dampered the fire down, but my speculation is that the damage was done.
In fire science, there is a term, "pyrolysis," which is a chemical process through which the ignition point of wood gets lower each time it is exposed to high heat. I've read that the flash point of wood can get down to less than 300 degrees. I figure that what happened is that the rafters, about 3 inches away, got too hot and started the combustion process. Over the next 5 hours it progressed to the flash point.
So, if you choose to go with the wood stove, here's my advice. Keep the stove several feet from the wall. Use a good wall shield that extends way beyond the boundaries of the stove and has over an inch of space between it and the wall. Don't use sheetrock...it's combustible. Hang the chimney from metal studs or whatever it takes to get it 6" or more from anything combustible. That includes ceiling and roof sheathing. Make yourself familiar with the code required clearances and manufacturer's recommendations and multiply by 3 or 4.
The friend who started the stove feels responsible. But I feel it was the designer...me. Fortunately, no one was hurt...there was snow on the ground and nothing else caught fire.
Reddog