Increasingly I hear from clients who want their sauna as a way to enhance their hot yoga (Bikram) practice. It’s a perfect pairing: what better way to follow up (or warm up for) a yoga session than with an even hotter sauna!
Recently a couple asked me to convert an old dingy freestanding cinder block garage into a sauna/ hot yoga studio. First I made sure the cinderblock wall was stable and did some minimal repairs. Then I isolated the block wall from the warm, humid space by adhering expanded polystyrene (XPS) foam board to the walls. This is critical as it prevents moist air from hitting the cold cinder blocks and condensing. Then I framed in the space, insulated the walls with mineral wool batts and finished the yoga space with drywall and the sauna with cedar (with the requisite radiant sauna foil layer and air gap). New windows replaced the old; the dramatic deep window recesses a result of the thick walls. Bamboo flooring over floating sleepers over foam board created just the right bounce for the yoga space, while the sauna has traditional duck boards. LED lighting added just the right ambiance. The heart of the sauna is the Harvia Cilindro heater with it’s 200 pound rock capacity. Amazingly, the old building was plumb and square— the original masons did a good job. Fighting an out-of-square space is the bane of all renovators.
This project was a complete transformation for this building (see below), turning it from a creaky old, under-utilized garage into a revitalized space for self-transformation. Make an inventory of the neglected spaces on your property awaiting transformation and give me a call!
You ask how or why electric mobile? There are a number of reasons why going mobile makes sense, especially if you rent. You need no permits or special permissions. You just park it in your yard and use it. You can take it with you on vacations or just for a Saturday down by the lake, you can even enter it in a parade. But why electric? Electric is no longer the inefficient dark horse of the energy world that it once was. It can be generated cleanly by wind or solar and is cheaper, cleaner, and easier to use than gas or oil. Although any purist will tell you a wood-burning sauna is the real deal, in some places wood is not so easy-—firewood may be hard to come by and to difficult store, and your neighbors may too close for comfort or offended by the occasional whiff of smoke. Since I’ve eliminated gas burners from my repertoire (for reasons I won’t go into here) an electric mobile sauna is the next best thing. All you need is a place to plug it in.
When clients ask me to create a sauna they often push me to do things I might have never considered doing. I’ve been requested to make saunas in spaces I thought were too tiny, on trailers, deep in the woods next to a pond, or to convert a cheap shed or laundry room. The most recent project to leave the shop is an electric mobile sauna. The owner has a Tesla electric car so an electric sauna just seemed to make sense. She also wanted the benches to flip up so it could be a mobile hot-yoga studio. The colors were more of an emotional choice: I painted it Sea Reflections blue like the ocean, where she likes to swim all year, with a Bonfire Red door to beckon her into the warmth of its interior, and Vanilla Ice Cream trim because, well, who doesn’t like ice cream, especially after a sauna?
The how, is simple: an 8 KW heater with a standard RV type hook up and a fifty-foot very-heavy extension cord that connects to standard car charging port (or special outdoor outlet). This will also work in many campgrounds with RV hook-ups. In a pinch, it can also be run off an 8500-watt generator.
This sauna also has a solar powered low-voltage lighting system, just so there can always be light and because low voltage systems are safer and more versatile than 120 volt lighting. I’ve been using these in some mobile wood burners and freestanding units. The neat little solar panel is a conversation starter; people are suddenly aware that the unit is more than a fancy tool shed trailer. When I tell them it’s an electric sauna, the little 25 watt solar panel gets a second glance.
What I envision next (but probably won’t consider doing unless a client pushes me) is a fully solar electric sauna. It would have to use Tesla’s 270-pound Powerwall home battery, which has an 8kw output capacity. I imagine the entire sauna roof would a have to be a solar panel but I haven’t done the engineering on this. This would not be cheap, but if there is someone out there who wants to be the first…. give me a call…
I just completed this bright blue, yellow and white gem of a sauna situated on a red deck. The color was the client’s choice; he wanted something that would brighten things up and be in stark contrast with usual suspects of taupe, dull brown, and moldy blues that afflict his neighborhood and so many other American housing developments. Why are builders so afraid of color?
The use of bright color in homes is often associated with places like seaside Baltic towns and Reykjavíc, Iceland—and for good reason. In the deep of winter these places are plunged into darkness as the sun hovers near the horizon or barely makes an appearance at all. Battling the winter blues should make the use of bright colors almost mandatory. Of course these places all have saunas too (or in the case of Reykjavíc, massive public hot springs), another way to survive the depth of winter. I also learned, when I was an artist-in-residence in Nova Scotia, that fishermen traditionally used bright colors in their houses simply because it’s left-over boat paint. Boats are painted brightly so they can be uniquely identified at sea, so, in a way, the colors express something unique about the individuals who live in there. Now, of course, the brightly colored fishing village is almost a tourist mandate.
Looking back on recent sauna projects, I see a shifting trend in color choices made by my clients. From authentic dark brown Viking tar, to blue-grey, then, brighter reds and blues and greens, and now, this latest color feast. There is also a trend in design to use more bright colors such as on the running shoes I saw in the gym yesterday that were an eye-popping florescent orange. I have been following the designer Ingrid Fetell Lee who writes about creating joy with color in her book The Aesthetics of Joy. She is persuasive about using more color for the simple reason that it creates joy. Although I teach color theory, I have a tendency to stick to blacks, grays and low intensity colors in my art, a trend that I have been to trying evolve out of. Perhaps I can take some cues from my clients and take some color risks in my own work. This latest sauna project actually makes me think of a late Mondrian painting such as Broadway Boogie Woogie in which he reduced his palette to the three primary colors and sought to use color as the basis for expression.
In this latest sauna project my interest in sauna and art actually converged. The warm interior heats your body and the colorful exterior warms your spirit. Thanks, Karl!
I just completed a large (9×12 foot ) sauna at Silverlaken Glampground near Letchworth State Park. This is such an ideal setting for quiet retreats or group gatherings: a main lodge in a historic cottage, private cabins and luxury tents next to sparkling Silver Lake just miles from one of the most popular state parks in New York. The sauna is the perfect centerpiece for small or large gatherings. A group sauna is different than a small intimate home sauna; it is a unique social situation where you may commune with strangers and make new friends all while stripped bare of the trappings of social status, class or superficiality. It can be a perfect setting for friends to solemnly celebrate life’s important moments: a reunion, a wedding, a men’s retreat or whatever occasion that will be enhanced by closeness and shared exhilaration. The sauna easily holds a dozen or more bathers and is a stone’s throw from the lake.
As I always do, I tested the sauna before leaving a finished project. The new owner was elated as a I brought it up to temperature while I explained the intricacies of sauna; after a round we jumped in the brisk lake. It was the perfect way to end an exhausting effort and make my long haul home a relaxing one.
If you are in Western New York and looking for a unique place to stay and want a sauna experience, I recommend you checkSilverlakenout! (listed on Airbnb)
I get a lot of questions regarding sauna insulating details and thought I’d shed some light on a few issues. A caveat before I start: heat transfer science gets pretty complicated and I am grossly simplifying things here. I’m not an engineer but I rely on experience and am constantly probing and measuring my own saunas to see what works. A building inspector may want an engineer’s input, but just make sure the engineer understands what happens in a sauna.
If you are building an electric sauna, either in your house or as a stand-alone building, you’ll naturally want to insulate it for efficiency. Normally builders (and building inspectors) think of R-value (printed on every insulation product label) as the golden metric, and the R- values of a wall assembly are typically added up to get a number that either complies with code or satisfies a self imposed trade-off between cost, efficiency and practicality. R Value is the resistance to heat transfer but measures conduction and convection, not radiation, which is not much of a factor at lower temperature differentials. R values are calculated with normal living spaces and long term heat retention in mind, which in a typical home is calculated using an average temperature differential of 24°C (between heated and outside space). Since R= Delta T/ QA , (where QA is the ability of the material to transfer heat) and in a hot sauna Delta T might be 100°C, the use of labeled R factors is totally skewed!
The second factor is time. Heat loss is measured in BTU/ hr. With the sauna only on for few hours a week (bravo if it’s more!) your heat loss will be minimal and hopefully, in the cold months, will contribute to heating the house. So, in terms of cost vs. efficiency, a lot of insulation may be over kill.
At the higher temps of the sauna, the radiant effect of heat is more of a factor and the use of a radiant foil barrier comes into play. The heat you feel radiating from a wood stove is the long wave radiation. This radiation can move through common building materials but foil stops it dead in it’s tracks. Anyone who has nestled under an emergency blanket or protected himself from the fiery of a blast furnace, like when I pour bronze, understands the effectiveness of foil to bounce radiation back towards the heat source. But if the heat source contacts the foil layer, the aluminum superbly conducts the heat, defeating the purpose. So, when building a sauna, it is the radiant foil layer, with an air gap (on the hot side) that is crucial to holding the heat in. This should be backed by as much standard insulation as is practical, but don’t worry about attaining super R – value. The exception being if the wall is an outside wall of the house and a part of the building envelope- then, R-value must be a minimum of what the rest of the house has. I prefer Mineral wool, but in any case do not use XPS or EPS foam directly behind the foil, as they will melt at sauna temps!
Vapor control in an interior sauna is really important especially in modern tight houses, which tend to trap moisture, both for the damage vapor can cause that you can see, such as peeling paint, but more for the damage you won’t see, like moisture condensing in a wall cavity. Radiant foil barrier, when carefully taped at the seams, is also a perfect vapor barrier. When I build interior saunas I think about all of that moisture and imagine where it can get to and wreak havoc. I then seal off those spaces but provide a vented path for it to escape. Some enthusiastic löyly action will turn ladles of water into steam which fills the sauna but then escapes into the house— like when you forget a kettle on the stove and all your windows fog up. The best thing is to build your sauna next to a shower area and then vent that area with a decent bath fan to the outside or via the household HRV system. The sauna should then have an air intake under the heater as per manufacturer’s instructions and via a gap under the door so sauna gets a healthy exchange of fresh air. Never connect the sauna directly to a mechanical ventilation system.
With careful planning of layout, insulation, ventilation moisture control, and a heater that makes good löyly, your indoor electric sauna can feel like a wood burner on a pond’s edge but also be an integral part of your efficient home. (Read more about Sauna foam and best sauna building materials at Sauna Insulation, Revisited)
My latest project came about because of the enthusiastic insistence of the client, who, with typical Finnish ingenuity, decided that her tiny “garden shed” needed to become a sweet little sauna. Typically, for the electric saunas I build, I carve out space in the recesses of a dark basement or some other unused corner of the house; this one had its own bright little shell for me to work with, perfectly placed a few paces from the kitchen door. The exterior had its own charm, so I left that alone except for the new galvanized metal roof, which mirrors its surroundings. It is clandestinely tucked into the yard so that, unbeknownst to the neighbors, there is a whole world of warmth inside.
It immediately reminded me of a Tardis—which, for those of you not up on Dr. Who, of the popular British TV series, is a time machine in the form of a phone booth; when the door is opened, an enormous interior is revealed (Tardis is an acronym for time and relative dimensions in space). My challenge was to make this 64 square foot shed completely functional as a sauna and feel larger than it is. So far it has surpassed my expectations: it feels roomy, airy and comfortable for 2 or 3 people with a heat that burns deep and a löyly that lingers just long enough. I even fit in a foyer/disrobing area. Stepping out of it in a cloud of steam it is hard to reconcile the size of the outside with the comfort of the interior.
Like the Tardis, the sauna is a time machine; once inside, the heat takes you to another dimension as minutes turn to hours and worries melt away like the face on a Dali watch. Sometimes I want to thank my clients more than they thank me—for the inspiration to create something so perfect and for taking me out of my world and into theirs.
Looking back on recent sauna projects, I see a shifting trend in color choices made by my clients. From authentic dark brown Viking tar, to blue-grey, then, brighter reds and blues and greens, and now, this latest color feast. There is also a trend in design to use more bright colors such as on the running shoes I saw in the gym yesterday that were an eye-popping florescent orange. I have been following the designer Ingrid Fetell Lee who writes about creating joy with color in her book 
