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Electric sauna heater review by a professional electrical engineer (Part II)

Please re-welcome Jeff back to saunatimes for Part II of his electric sauna heater review.  Jeff is an electrical engineer by trade. He has a high end job. I cannot reveal Jeff’s actual position. as I could be tracked down and interrogated by folks in black suits for breach of National Security. 

Enter Jeff:

In part 1 of this series (link here), we looked at various aspects of electric heaters. This includes sizing, styles, and design that differentiate some of these units.  In this post, we will explore some more of these topics, in addition to looking at construction and available amenities. For those looking for something a little more exotic, we will also take a look at gray market heaters.

Our previous post discussed how the overwhelming majority of electric sauna heaters are of the same basic design. These electric stoves don’t really have all that much to discriminate among them.  The market is dominated by two big companies, Harvia and Tylo-Helo, with rebadging of common units between model lines to create an appearance of variety.

On top of this, in general. only the blandest models have been certified for the North American market.   The manufacturers just don’t want to spend the money to certify a model unless they’re sure sales will justify the cost.  While understandable, it results in pretty pathetic selection for the North American sauna enthusiast.  Probably 80-90% of the models offered in North America are the same basic bland design; a wall-mounted box, deep rock cavity, 40 lbs of rocks, with three heating elements in direct contact with rocks.  Ho-hum.

same basic design of a conventional electric sauna stove

Two different product lines from Tylo-Helo, the Finnleo Designer (left) and the Polar HNVR (right), notice any similarities?  It’s not a coincidence.  In part 1 we show how Harvia markets the same unit under the Harvia and Finlandia brand names. 

Don’t get me wrong, this isn’t all bad.  There is an upside in that it does give the savvy consumer more options for bargain hunting.  If you’re on a tight budget and satisfied with the basic North American offering you can price shop among different “brands” and know you’ll get pretty much the same thing.  You may like the Finnleo but it’s only stocked by a few distributors.  You might find a deal or a close-out from some other distributor on the Polar (or visa versa).  It’s something to keep in mind as you steer through the marketing hype put out there from the manufacturers.

Electric sauna heater review: Tylo Units are Genuinely Unique

As mentioned in part 1, Tylo is the real outlier in that its units are genuinely unique.  We previously discussed the side chambers and staged heating elements but Tylo also uses unique chassis construction.  Tylo’s units have a carbon fiber surface coating that stays cool to the touch, unlike pretty much every other unit out there.  This means that Tylo’s don’t require a heater guard though Tylo does recommend you use one.

Heater guard on an electric sauna stove

Don’t want to use a heater guard like this for whatever reason?  Tylo’s cool touch surface coating means it isn’t legally required.

Tylo also is unique in that its remote control units house all the electronics within the heater itself rather than having a remote contactor box used by most of the others.  This certainly simplifies installation. However, I’m not sure this is a good thing in the big scheme of things, as the hot room environment increases wear and tear on the electronic parts themselves.  Tylo also has its own angular styling that is starkly different from the “box on the wall” look of most of the others.  Beauty is in the eye of the beholder, but I think they look pretty cool.  Plus, you don’t have to hide them behind a heater guard so people can actually see it and appreciate its appearance.

This isn’t meant to say that Tylo’s are better or worse than the others. But, they are definitely different from the standard North American offering.  If you are looking for some diversity in choice, they are worth checking out.  Fair warning, they are generally a bit more expensive than their equivalent “box on the wall” counterpart.

You Really Should Consider Lots of Rocks

Glenn has commented that he can tell an electric-heated sauna from a wood-burning sauna even if blindfolded. He equates an electric-heated sauna to sitting inside a toaster oven.  While I think his comment was somewhat tongue-in-cheek, the maestro does have a point.  However, I would suggest that the difference is not caused so much by the actual heat source, but by the rock quantity.  Heating a sauna with a blazing camp fire rather than a rock-filled stove wouldn’t be very pleasant either.

We got into the physics of rock quantity in part 1 and I won’t rehash that here. However, I will remind folks that rocks create thermal capacitance.  Sauna rocks store heat and provide for a soft, even release and distribution over time.  Take a look at some popular wood–burning stoves recommended for family-sized saunas below and note the rock quantity.

Sauna stove rock mass creating thermal mass for a better sauna experience

Now compare that to the typical electric box-on-a-wall heater that at most holds 44 pounds of rocks.  When it comes to thermal capacitance, these electric wall-mounted units just can’t compare to the wood-burning sauna stoves.  That’s the price you pay for convenience and compact size.  If you want to try and replicate the wood-burning feel with an electric heater, you’re going to have to increase the rock mass.  There really just isn’t any good way around this fact.

What I chose

For our sauna, we tackled this by selecting a floor-standing electric heater (rather than a wall-mounted unit) that holds up to 110 pounds of rocks.  It’s a 7 kW unit that is a little oversized for our 240 cubic foot sauna. We didn’t want to endure long warm-up times that would result from having such a large rock quantity.  Also, we made our sauna ceiling lower that the usual, averaging about 6 feet 6 inches.  We originally did this to minimize overall structure height.  I later realized this would also help with warm-up times as we aren’t wasting heat pooling well above our heads.

Our Harvia Virta floor-standing unit during a fit check, note the deep rock cavity (rocks and heater guard have not been installed at this point). Despite its size this unit only needs 2 inches of clearance around it so it fits in a really tight and compact space.

This isn’t meant as knock on the wall-mounted units. Wall mounted sauna heaters certainly have their place particularly if the budget is tight. However, there are trade-offs involved. There are other options available with large rock capacity that may be a better choice.  Check out some of the more exotic models available and don’t assume the predominance of the wall-mounted units means that they are necessarily the best way to go.

Other Amenities – Combi Units

Sharp-eyed readers may have noticed that our unit shown above is actually the Harvia Virta Combi as opposed to the standard Harvia Virta.  Combi units include a water tank and a dedicated heating element allowing higher humidity levels than typical Finnish sauna heaters.  You can still throw water on the rocks to create bursts of löyly in the traditional fashion.  However, in addition to setting the temperature level you can also set a precise humidity level higher than that usually used in saunas.

Harvia Virta Combi (left), note water tank with internal heating element in front of main heating elements. Tylo Sense Combi (right) has a water tank with built-in heating element located behind the rock cavity.

The idea behind these units is not to create a 100% humidity Turkish-style steam bath, as this would ruin most wooden saunas over time.  Instead, they create what’s caused a “soft sauna” with 40-60% humidity and lower sauna temperatures.  Combi units provide an extra degree of flexibility, particularly for those from different sweat bathing traditions.  I originally proposed this model to get my wife on board. Her ethnicity tends to favor steam whereas I wanted a dry Finnish sauna.  The Combi is a bit pricey, but overall is a small cost to keep my wife happy.

One of the really nice features of these units is that they can be set to automatically run a 0% humidity cycle to dry out the sauna immediately after steam bathing.  In addition, we’ve also included an exhaust fan in our sauna that is automatically activated at the start of the drying cycle to quickly remove residual humidity.  Both are controlled by the Virta Combi and should help prolong the life of the wood in our sauna.

One other thing to consider for outdoor saunas is that water remaining in the Combi tank could freeze if left unattended in cold climates.  This isn’t an issue for us in Southern California but something to consider if this applies to you.  The manufacturers recommend the user should drain remaining water after each use.

The “Always On” Sauna Heater

The “always on” sauna heater may be worth considering.  These units contain the rocks within a super-insulated cavity with a closable lid that keeps heat trapped inside the box.  There’s a low power heating element (usually around 200 Watts, about 4% of the main elements) that runs more or less continuously and keeps the rocks at sauna temperatures.  When you’re ready to sauna, you simply pop the lid open to quickly bring the sauna room to temperature.  Since the rocks are already hot, warm up only consists of that necessary to heat the air thus greatly reducing warm-up time.  Once opened, the main heating elements kick-on as needed to maintain the rocks at sauna temperatures.  These units typically have fairy impressive rock quantities for lots of thermal capacitance.

The Harvia Forte (left), Finnleo Saunatonttu (center), and the Polar Saunatime (right) are always on units. The Saunatonttu is pretty cool-looking but I can’t help thinking of R2D2. As to the Polar “Saunatime”, I think our host might have something to say about that name.

There are two downsides to these units; the purchase price is relatively high (at least $2K, some upwards of $3k) and the potential operating costs.  If you sauna regularly (nearly daily) then the costs of operating the low power element should more or less pay for themselves in reduced high power element operation.  If you sauna maybe once a week or less, then the electricity cost perspective is not worthwhile.  As an example, the 200 Watt element on continuously for 24 hours will use 4.8 kW-hours of electricity, the same as operating a 4.8 kW high power element for one hour.

So even if you don’t use it often, your electric bill will look comparable to a standard electric heater being used daily.  Perhaps this doesn’t concern you, but it is something that should be considered when planning the sauna. And this electric sauna heater review is here to help.

Electric sauna heater review: Gray-Market Heaters

Suppose you just aren’t happy with the sauna heater selection in North America.  It’s understandable as the vast majority of those certified for our market are uninspiring compromises, designed to appeal to the most people possible.  It is as if every restaurant being a pizza parlor or burger joint.  I’ve singled out some notable exceptions (in my opinion) in this post and the previous one but what if one is looking for something more?  Take a look at this screen capture from a UK sauna distributor as part of this electric sauna heater review:

A UK sauna distributor going deep

Aside from a few exceptions (e.g. Harvia and Tylo), most of the brands aren’t even available in the US as these units haven’t been certified here.  Also consider that these brands have multiple product lines. You’ll see if you click through each of these tags, many of them can be seen in the screenshot.  We probably get 10% the choices available of the European consumer, and the choices we do get are the pizza and the burgers.  So why not buy from Europe?  It’s certainly possible though there are some real potential pitfalls.  I won’t discuss the legality of doing so as I’m not a lawyer.  If you choose to do so, it’s between your conscience, the insurance man, and our friends at the Underwriter’s Laboratory (UL).  Proceed at your own risk.

Power incompatibility

With this electric sauna heater review, power incompatibility is the main issue when buying from Europe.  The great majority of European units are configured for 400 Volt three-phase power, not the 240 volt single-phase power available in North America.  There are some 240 units available from Europe but the selection isn’t much better than that available here.  Most 400 Volt units likely can be converted to North American power as the single-phase voltage forms are comparable.  (Each “leg” of 400 volt 3-phase power is 230 volts, virtually identical to the 240 Volts available here.)  However, they will almost certainly require additional contactors, fusing, and rewiring.  It’s definitely not a job for amateur hour.

Notation and wiring denoting 400 Volt 3-phase power from a European Harvia unit. This won’t work in North America without being reconfigured.

Further, North American units require a self-contained over temperature sensor that shuts the unit down in the event the inside of the heater gets too hot (usually 240 deg F).  European units don’t have this. They rely on the room temperature sensor for an over temperature trip.  Most of the European manufacturer’s seem to slap these on North American units as an afterthought and frankly they don’t seem to work very well.  Older Tylo units in particular have a reputation for tripping at much lower temperatures than they should.  In some documented cases, these trip at such a low temperature the sauna room can’t go much above 160 deg F.  The “fix” is to move the bulb sensor lower in the unit so it doesn’t get as hot.  I mention this as this safety feature seems to cause more problems than it actually solves.  Presumably the North American manufacturers (Saunacore, Scandia, etc.) do a better job with this.

More on grey market heaters

There are a few other odds and ends that a gray-market buyer must consider.  North American regulations limit interior sauna temperatures to 194 deg F (30°c.) and also limit the maximum sauna heater time setting to 1 hour.  European units wont meet these constraints as they will allow higher temperatures and longer times.  North America also requires a guard or grate over the top of the rocks.  European units won’t have this grate and they probably don’t even exist (in the event you wanted to obtain one) for units that aren’t certified for North America.  Violating these requirements will probably get you in trouble with the same guys who enforce the prohibition on tearing off those mattress tabs.

Last off, delivery can be an issue as the European distributors I contacted were willing to just get it to the US (for example a customs broker in New York) but wouldn’t ship it to my house.  That part I had to figure out myself.  I ultimately decided it was too much of a hassle.  You may find it worthwhile and the European prices are generally very good and quite a bit cheaper than comparable certified North American models.

Electric sauna heater review: conclusion

Thanks for reading and hopefully readers found this and the previous post helpful.  I would appreciate hearing from any readers that have brought in gray-market heaters and how their experience went.  Either leave a comment or send an email to Glenn so he can pass it along.

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35 thoughts on “Electric sauna heater review by a professional electrical engineer (Part II)”

  1. Have you looked into the Kumma electric version? Additional bonus, they’re built in the US.

  2. i have a tylo sport 8, big fan. could be psychological but those side air chambers really seem to help heat the sauna quickly.

    regarding controls on the unit itself, this should be a non-issue. the electro-mechanical control components are simple and rugged. plus they are located at the bottom of the unit, just a few inches off the ground. so while it may be 200 degrees at the ceiling, it is only around 90 degrees or so down where the controls are located.

    this post inspired me to pop the cover off the electrical section of the heater and take a peek. after 275+ saunas with the heater, everything looks as good as it did when i first took it out of the box.

  3. I’m still in the planning stage of my own sauna. Does anyone have experience with an electric heater that has 110 lb rock capacity and a wood burning stove with approximately the same rock capacity? I do not and was wondering if you could tell the difference? I live in a metro area and will need building inspector approval. Going electric would be easier, but wood burning tickles the soul. Thanks.

  4. sean, head down to your building inspector office and talk through it with them. most departments are more than happy to work with you to make sure things are done right. biggest question would be if a wood burner is even allowed. not for safety reasons but zoning reasons. many urban municipalities in the north have banned backyard wood burning boilers due to the stack discharge being close to the ground compared to the top of a roof. the lower smoke lingers, drifts into neighbor’s yards and folks get upset. an outdoor wood-burning sauna could fall into this category. one difference is that a wood burning saunas are typically only operated for a couple hours a couple times a week. compare that to a backyard boiler that is more or less burning 24/7.

    my particular village banned new backyard boilers a couple years ago but agreed that a wood burning sauna is not the same thing and they would allow it. i went electric anyway for different reasons but the point is if you talk to them up-front, good things can happen!

    you’ll definitely have to get a ul-listed stove and install per the manufacturer’s instructions, whether you go wood-burning or electric. be aware that wood burners typically require more clearance around the unit (or additional heat shielding) which require more floor space which leads to a bigger structure and so on…

  5. Miller – Love the fact you opened up your Tylo and gave it an inspection, a typical engineer! I’d have probably done the same thing. My concerns about the electronics were more aimed at the programmable units as the micro-controller is inside the heater itself in close proximity to the heating elements. The others tend to locate them outside the hot room.

    It’s a theoretical concern rather than an actual documented issue, primarily based on my professional airborne/space experience with late test failures during environmental tests. One of those things where you get burned early in your career and it affects decisions for the next 25 years. I’ll admit is probably being overly conservative.

    I certainly don’t mean it as a knock on Tylo as they make a good heater. They also have the longest warranty of any of the manufacturers that I’ve found, so they stand behind them. I like their units as they show real creativity in design and styling, unlike some of the others. Hopefully that came through in these posts.

    Jeff C

  6. I would encourage anyone reading to check out the Himalaya heater from TyloHelo Inc. See http://www.finnleo.com

    This is as close as you can come to a wood fired sauna. 200 pounds of rocks and the new BWT system create a sauna that takes you back to your wood burning roots. And it looks incredible. Yep. I sell saunas. And I also use them. Check out this Himalaya. It’s worth the time

  7. Heya Jeff! I’m an engineer who has some interest in operation of the Harvia Xenio controller and would love if I could lean on you for help with a couple questions I had. I sent an email to admin who can connect us if you’re interested.


  8. Well it just so happens I know quite a bit more about them than I originally intended since mine had an intermittent fault I had to hunt down and fix with an o-scope and a can of freeze spray. Working great now.

    Glenn – Please forward Bradley my email address if you can.


    I first bought a genrador de vapor from a website in Toledo from a person named Jesus, he said he will send a 5.5 k due to the size and sent a 4.5k, i then asked for 2 months that he came to install it, he refused and kept saying, to finish the saune to install it.

    After 3 months i realised he will never come to install it, i contacted Harvia in Finlandia to ask for another tecnician, i was told Harvia do not operate outside Barcelone. The person from Finlandia Pekka told me, she will find me a tecnician and the distributor saunapoolespana.es called me , told me the following:

    we do not have a tecnician to install your generador, but a tecnician who install hydromasage to whom we will send a manual so he can learn and come to install it for you??

    i was skeptic and waited but finally nothing happenned, Rosa said the tecnician do not respond to the phne anymore…..

    i insited and they finally found someone for not 340 e but 580 e finally who could install it, from barcelona or alicante?

    but after the instalation upon leaving they never tested it, the sauna was not going over 23 degrees.

    i burned my fingers trying to set it up and spend the night on the manual to find out all the problems during instalation…contcated back Rosa from Saunapoolespana.es she told me this time we will send you a resistence to go up to 6kw, its the same unit from 5k to 15k only the resistence chnged? why not taking more resistence while seting it up in case? no they didnt now took more resistence and they didnt even try it out. and leave me witha suana at 23 degrees .

    i was told to inform Rosa after receiving the resistence so she can called Juan Carlos sat Burmar Alicante, but she didnt called him.

    she told me he will pass monday, then she told me he will be everyday in valencia so no problem he can pass anyday after you got the resistence, so when i got the resistence i asked when will the tecnician pass, she said finally he can not come until he finsih his job in valencia? he will come next week?

    i have no idea of the turco bath will work, i still wait since 3-4 months, i realised how bad the situation is , how much i was abused by all, when i told them they do not even feel guilty, they think all is fine ith them, so i let you read and understand this.

    never buy from Harvia or saunapoolespana.es, you have been warned!

    since then we replaced the resistence with one of 3600 watts, now the generador is of 6.6kw and it does not go over 33 degrees in 3 hours.

    I want contact the president of Harvia.
    I bought this generador 4 montsh ago, i burned my finger and contcated 3 diferent places to have a decent instalation in vain, I wanted to reprot the attitude of Rosa, she said after all, she is not responsible for my problem as she didnt sold me the generador.
    she lied to me saying they will update the resistence very quickly after i received it, the tecnician, 5 days after was not even aware of it.

    Catastrofico, no hay sufisente espacio por decir lo que quiero decir, saunapool.es es una alienacion, un otro maldito distributor, harvia eres tan mal representado aqui, , senor no tenemos tecnico, vamos a enviar un libro manual a un instalator de banera, por que el lo aprendes y despues pasaria instalarlo, pero el tecnico despues no queria contestar el telefono, eso es el servicio pro de harvia, pues me enviaron un tecnico por doble del precio 580e que me dejaron el generador despues 4 horas a 23 grados….asi es el profesionalismo de saunapool.es y en ningun caso se sientes responsable.porque no me lo a vendido, pero tampoco la representacion de harvia y su responsabilitad de ser mayor distributor de espana, eso tampoco no lo respecta, gracias saunapool.es de hacerme entender el moro hijos de puta que soy por ti

    cuando es el momento de areglar todo y cambiar de resistencia, me dicieron que el tecnico pasaria rapido despues por areglarlo, me pregunbtaron de enviar un mensaje cuando recibo la resistencia por instalarla en un tiempo deciente, pero no aun, no se pasara asi, nunca ellos tenia avisado el tecnico, de lunes, a cambiado por otra semana y asi es, depsues de 4 meses de lucha con Harvia, el mayor constructor de sauna de finlandia, o la violencia de los corporacion, toma lo como quieres, este atituda son vieja de 50 anos, son los misma atituda de violencia de alienacion que existe desde 50 anos.

    1/ the agente Harvia who sold me the generador have me waited 2 months to install it and let me down without installing it!
    .2/ saunapool.es mayor distributor de espana, me alienara con la historia de enviar un manual a un desconocido que luego no contesta ni a ellos el telefono, eso podria gente en confianza si claro…
    3/ me enviaron un instalador a dos veces el precio que me dejas con un sauna a 23 grados!!
    4/ ahora que falta cambiar de resistencia me dicieron que el tecnico pasaria el dia despues, pero nunca lo llamaron, eso estaba por alienar poco mas,
    5/ saunapool.es me dices, no estamos responsable de tu problemos poruqe no te vendemos el generador, vees como un distributor nacional se quita toda la responsabilitad,

    6/ por fin Rosa me deciera que me enviara una otra resistencia de mas, y nunca lo a echo

    7/ sat service por reparar el generador me tenia dicho que podria llamar el en caso de problemos pero despues de hablar con Rosa el abuso de poder, el tecnician no quieres venir no mas, eso es la ayuda de saunapool.es el unico distributor de Harvia en Espana, gente, buena suerte.

    8/ the control panel should have been installed outside

    9/ the resistence of 3.6 kwt can not be added to this genrador,

    10/ the cable electrical connection was done very badly.

    11/ I will never trust Harvia, i feel being ripped off, misguided too many times, they lied to me and installed it dangerously and i do not see a good solution except asking me to rebuilt my sauna now.

    12/ The control panel broke due to the fact the instalador set the panel inside. 250 euros.

    Harvia. you re one of the most violent corporate i dealt with for a long time, if it was to redo now, I will never choose your product.

    despues de comprar el generador y llorar 20 veces que me lo installa el agente me enviara unos fotos de el con su caballo, la verdad, lo digo por harvia, yo lo que queria es una instalacion correcta, no un chaval que me envian foto de el con su caballo, pero que tipo de agente tienes a Harvia!!!!

    nota que los generadores de 5kwt a 15kwt son los mismos, lo que cambia es la resistencia, tu piensaria que el tecnico tomaria algun resistencia de mas , tu a esperando 3 meses o 4 meses, el te carga dos veces mas vienes de muy lejos, no toma ni una resistencia de mas, ni mira si el sauna se claiente? normal, si es normal, lo dejo a ti, que vas a leer lo, por fin peudeser que harvia funcionna con este gente de marbella, y como muchas cosas en este pais, es reservado a los muy ricos, si tu estas con dolores de artrosis, con Harvia, tu puedes comer la M ….a. gracias

    por los medidas, nada es vale, los informaciones son falsa, por algo de 8 metros cubos echo a exterior te falta minimo 9kwt por calentar lo y es 2 horas por calentar, al final es mucho electricidad, y mucho mas grande aparato que te falta, no te fias a lo que dicen, entre algo echo a exteior y algo interior , ellos no hacen ningun diferencia y es falso.
    lo hicemos con mucha isolation y no cambio nada, el tecnico diciendo es muy bien echo , tendria mucha calor enates de corir saliendo…y la otra que te dices al final que tu sauna es mal echo….
    primero ca,bio de resistencia, tenia a llamr un electricista, tenia a recibir segunda resistencia, pues no a sido enviado, claro. gracias

    el sensor de temperatura, en el libro dicen de instalarlo arriba donde hay mas calor, con silicona, y que solo 0,7 mm del sensor sale de la pared. yo lo tengo instalado asi:
    saliendo de la pared de 4 cm, instalado abajo de la pared en un tubo suleto sin silicona con aire frio entrando. eso es lo de los 580 euros por la instalacion
    el difusor de vapor en direcion de una puerta de cristal muy fria. sin rellenar los agugeros echo por error en la pared, sin limpiar nada de la obra despues, sin verificar que se calienta, sin que el tecnico vuelves por ayudar y installar los dos resistencia de mas que me faltaba.

  10. Glen or any one else, have you heard of any one with experience with the Harvia Cilindro? It seems like the high stone capacity could prevent the Toaster oven effect. Plus it looks way better than the standard electric heaters.

  11. Brennan: I have not yet taken a sauna heated by a Harvia Cilindro. Intuitively thinking, i’m right there with you. And the folks that designed it were right there with us, too, as a way to build heat and thermal mass (vs just toasting the skin). Let’s see if others chime in on this score.

  12. Hey Steve, I have been looking at the Tylo Elite as well but have not had much luck getting any user feedback. Would love to hear if you come up with anything.

  13. I bought a house with a sauna installed with a Finn Star heater. I can’t find anything about this brand and the various service people I called haven’t heard of it either. It seems to be working — although perhaps not hot enough . I’m not sure if coils are worn out. Do you know anything about the brand ? Is it worth a tune up or should I save the service call $ and buy a new heater ? I’m betting it is from the 1990’s. Your site is really helpful!

  14. Glad saunatimes is helping you. I don’t know Finn Star heaters, either. And Jeff is the guru of electro saunas. If the stove isn’t working up to par, my suggestion is to not bother with the service call (most electricians run away from servicing electro sauna stoves) and put money towards one of the electro stoves that Jeff recommends within this guest post. Good luck! sauna on!.

  15. I am in the process of building a backyard sauna in SW Minneapolis. Planning to buy a 9kw Huum Hive Hester. It’s CE approved (apparently working on UL) and comes wired for 240. Includes a wireless controller so you can turn it on or off via your mobile phone. Available from sellers on Amazon and on eBay. I think the hive holds 300+ pounds of rocks which seems like plenty!

  16. Hello,

    I am building an outside sauna in Canada. It will be insulated and have 2×6 exterior walls with a concrete slab. The actual floor size of the sauna is 392 sqft (8′ wide, 7′ deep, 7′ high). I am planning on having a larger window plus two transom windows (all windows insulated double paned). The total square footage of the windows is 22 sqft. Based on the rule of thumb it looks like my total square footage is about 490 sqft. Will a 10.5kw heater be enough to heat this space? I was looking at something like Helo Himalaya or Laava. Would these heaters work or am I missing anything? Obviously, i am just worried about the sauna not being able to reach a high enough temperature.


  17. Hi, Jeff and/or Glenn. Such great info! I have a friend who requires an electric heater. He purchased the Kuuma electric stove but ran into issues with the city he lives in due to it not being UL certified. Of the options you mentioned in the article, do you know if the Harvia Virta 7 or the Hariva Combi are UL certified? I don’t see the specifics of this anywhere in the fine print. Further, if it has to be a UL certified unit, are the options only the “bland” ones you mentioned?


  18. hello! Just looking at the Harvia Virta Combi, and wondered if you had any further feedback on it after using it for a while. Would love to hear your likes/dislikes on it. Thanks!

  19. Thank you Jeff and Glen. Great article! You mentioned that you can adjust the bulb temperature sensor lower in the heater to prevent shut offs. Where is this bulb typically located? Is is possible to disable the sensor? I have a cheap Coasts wall mounted sauna heater (9kw) in my 6ft barrel sauna.

  20. Hi Greg – Just noticed your comment from back in May and hopefully you’ll see this if you have not bought already. We love the Virta Combi, it is a fantastic unit. It heats quickly and evenly and you wouldn’t even know when the heating elements were cycled on (if not for the click of the relays) because the delivery is so smooth over time. No “toaster oven” effect whatsoever. We’ve had no issues with ours after three years of pretty regular use.

    One thing to keep in mind is that the instructions say to place the heat sensor at the top of the wall directly above the heater. Big mistake. That’s the absolute hottest part of the room and doing so will limit how hot the room can get (I suspect Harvia suggests that location for legal reasons). Also, the elements will cycle on and off more. After about a week at that location I moved the sensor to about six feet away and put it at eye level. The room goes a good 20 degrees hotter and the heater doesn’t cycle on an off as much.

    One thing that really surprised me is after the sauna is warmed up the elements are only on about 20% of the time to keep the room at temp. The sauna is well insulated and we’re in a moderate climate but still, I don’t even think we noticed a difference in our electric bill.

  21. Hi Jeff and all —

    Just got my new sauna up and running here in Seattle. I used the Harvia Cilindro 11.5kw with the Xenio controller.

    I would definitely give a thumbs up on this heater. The thermal mass of those 250 pounds of stones is very helpful. It takes about 2 hours to heat up right now. I’m spoiled and used to 240 degrees (http://www.banya5.com/ is my local place but Covid-closed right now). I am getting up around 210+.

    I have a few observations if anybody’s going this route — and would love any input (hello Jeff??? or anyone).

    First issue is that the Xenio controller will only run for 1 hour max. This is crazy, of course, since it takes a couple of hours to heat up so I need to remember to run outside several times while it’s heating up. Apparently there are version of the same controller that can be programmed to run for longer in “commercial” contexts, but apparently the unit that came with mine can’t be. I do wonder if there’s some internal configuration switch that can be toggled to enable this. Right now I’m thinking I need to relocate the control panel 50′ away in my house so I don’t have to go in and out, but if anybody has done any hacking of that controller I’d love to know!

    Second issue is the overheat sensor. Usually once while heating up and again while using the sauna the overheat sensor will trip. This is a pain when I’m still trying to heat things up and I get out there to find the heater’s been off for half an hour :-(. I know all the US heaters are really aiming at the 194F UL limit, but I’ve been wondering about the wisdom or effort of messing with the sensor. Maybe replace the NTC thermistor with one that’s that has different heat behavior. Or have an manual override switch with the sensor? Any idea if it’s just an open close switch that goes to the contactor box? Other advice? I have been warned that having the sensor trip a bunch may not be good for the heater components which might mean the sensor itself (which I’d be will to take a chance on needing to replace) or it could mean the main heating elements (which I don’t want to mess up!).

    Anyway, long post with some sharing. Would love any input from others about these Conundrums.

  22. David:

    I’m pleased to let you know that Jeff is in the cue for being a guest on Sauna Talk! I’ll bring up your issue with him during our chat, if he hasn’t responded here by then.

    Also, regarding Xenio controller running for one hour max. Imagine the Xenio marketing department trying to spin that shortcoming around: “We at Xenio acknowledge the origins of sauna being wood burning. As such, in tribute, we’ve created ‘log-reminder™’. Instead of adding a log every hour, you simply press a button!”

    Back to reality, and as you know, the time limit is a safety thing. Safety first.

  23. Folks, your website is a great source of information on all things sauna. I did the calculation of wood vs electric – and chose electric (based on my budget and based on an estimate from my electrician) as the cost of the stainless insulated pipe for climate here in MA was more than the stove!) Yesterday I had my electrician install a Harvia Cilindro HPC-HP 9.0 KW Electric Sauna Heater and it took two guys better part of a day to do the complete install to a sauna shed that is 20 feet from my house. (50 amp breaker in basement panel, aluminum wire through underground conduit, external shut off panel at sauna (US code), into sauna wall w temp-rated wire, connector and very tight difficult wiring into back of heater. Depending on the final bill from my electrician I would have been better off buying wood stove and the expensive stainless stove pipe system since I could have done the install myself to save $. Either way this is a $2K plus deal to purchase and install new wood or electric stove so folks need to be aware of costs including install as part of decision calculus – unless money doesn’t matter.

  24. Daniel: Over the years, i’ve slept well at night with tightly sealed foil on the inside and tyvek on the outside…

    “Tyvek is a non-perforated, nonwoven product with microscopic pores that are so small it still maintains excellent air and water holdout. But, Tyvek can breathe, which is essential for letting moisture vapor get out of your walls.”

  25. TWO HOURS for the Harvia Cilindro to heat up??! How big is the sauna? That’s crazy. I’m considering the 6.8kw Cilindro for a 4×7 and have read 30-40 minutes warm-up time. I may have to rethink that heater.

  26. I’m having a difficult time making a decision on an electric heater. We’re going with a 5×7 prefab and had picked a cilindro 7. I worry that it’ll look too big and take too long to heat, though was hoping that because its capacity exceeds our space, maybe not quite so long. The virta sounds like a better fit but is inexplicably $500 more expensive. I don’t want to spend a fortune, i.e. Tylo, but we are only doing this once. Or is a lesser unit with a few more rocks good enough? Help and thanks.

  27. Hi Glenn, Hoping Jeff might be able to comment. I have purchased and installed a Havia Virta 9kW with Xenio wall controller. I am now interested in if I might be able to connect a IoT device such as the Shelly 1 wireless relay switch to control on/off remotely as my sauna is in a detached garage. Has anyone done with a Harvia Virta heater and Xenio controller? Looking for guidance on how this might be achieved.


  28. Hi Glen,
    I’m working with a space with a fairly low ceiling height (below 6ft) but about 110 sf total. Do you think going below recommend ceiling height will cause censors to go on the fritz? I’m considering the type of heater you can just plug into a wall outlet, since my space is so small. Thank you.

  29. Looking for some advice on wiring.

    I purchased a 240V 6kW Huum Drop for my basement sauna.

    My understanding is that this will pull 25 amps (6,000/240 = 25).

    The total run from the heater to the box (through the controller) is probably less than 75′. Certainly less than 100′.

    I will have an electrician come by to put the breakers in, but I’d like to run the wire myself to save time.

    I have two questions and would be interested in feedback from people who are more familiar with electrical stuff than I am.

    1) Since it’s indoors, my understanding is that Romex wire is OK to run in the sauna walls without any kind of conduit or shielding. Is that the case?
    2) I’m torn between a 10 AWG (max 30 amps) and 8 AWG (max 40 amps). If it were in a non-Sauna application, I’d be find with 10 AWG. But I’m tempted to overengineer it and go with the thicker gauge because of the potential of higher temperatures (even though it come into the sauna fairly low so air temp should be low, but the actual heater is hot, so should I use the thicker wires?).

  30. Hi,
    I have a Harvia KV-80, 8 KW heater.
    Heater works fine, but I think the thermostat is faulty.
    I set the temperature button, to say 180F, and when the room temperature is 180F the thermostat turns the heater OFF.
    The problem is that thermostat only turns the heater On, when temperature drops to 150F.
    I repeated testing with different temperatures, but the difference was always the same about 30-35 degrees.
    I couldn’t find any specification for Harvia thermostat.
    To turn the heater on I have to cool the sensor , cover it with a cold wet napkin.
    Any suggestions?
    Thanks in advance

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