Electric Sauna Heaters

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Sizing an Electric Sauna Heater? Here’s Why 9kW is Probably Your Max

When building a sauna with an electric sauna heater, it is critical to choose the right sauna heater. Most everybody puts their focus on the hot room, but generally speaking, the main reason why 9kW is your maximum size electric sauna heater has nothing to do with your hot room. Want to guess why 9kW is your max size for home saunas? Here’s a clue:

Yep, you got it. The control panel. Homes in North America are single phase electric. Power comes in from the power company right to the electrical box. We can draw off power for appliances like clothes washers, arc welders, and power amps for heavy metal guitarists in the form of a dual breaker 20 amp circuit. 20 amp +20 amp = 40 amps. That’s good! We start pushing beyond this, and well, appliances can start tripping (without Psilocybin).

Now, when it comes to firing up our home saunas with electric sauna heaters (an oxymoron, I know) if we start trying to log jam a commercial electric sauna heater into our residential saunas, well, chances are you’ll be seeing colors and trails from your trips to the control panel to reset your circuit breaker.

Good News When It Comes to Electric Sauna Heater Sizing

9kW is generally your max. And 9kW is a great size for most residential applications. And 9kW is the max that sauna heater manufacturers UL certify. You can refer to sizing charts on sauna heater manufacturer websites. What you will find is that a 9kW fits a 6’x8′ or 7’x7′ or even an 8’x8′ hot room like a baseball glove (and not an OJ Simpson glove). To best understand sauna heater sizing, consider that an electric sauna heated sauna performs best when the stove is “on” no more than 30% of the time.

An Electric Sauna Heater Undersized for Your Hot Room Will:

  • be on too much.
  • suck the oxygen out of the room.
  • overheat the rocks and your ears.
  • give löyly that will make you want to rush out the hot room door.
  • be apt to provoke your guests to say “This sucks. I don’t like sauna.”
  • incur increased energy consumption: the heater runs more frequently.

A Sauna Heater Oversized for Your Hot Room Will:

  • be on too little.
  • heat the room too fast.
  • underheat the rocks, and your body, and your soul.
  • give löyly that will make you feel like a wet diaper (wimpy and wet).
  • be apt to provoke your guests to say “This sucks. I don’t like sauna.”

Do you get the idea of how important this is? 9kW is the max for residential purposes. Let’s size our hot rooms and heaters appropriately.

There’s always the potential for a bigger hammer. You’ll sometimes find commercial sized electric sauna heaters in residential homes, especially newly built mega homes with big ass basements that go on and on. In these instances, the electrician will need to install an 80 amp breaker to carry the load of a 15kW sauna heater, for example.

How to Properly Vent Your Electric Heated Sauna

Whichever sauna heater you choose, venting your sauna is important. Each manufacturer provides a different drawing and instructions. The major consideration is mechanical ventilation or standard non mechanical ventilation.

If mechanically venting your sauna, heated by an electric heater, locate your intake vent just above the sauna rocks. If venting your sauna without mechanical ventilation, you are best to allow for a generous gap along the bottom of your sauna door.

The best move is to be able to vent your electric heated sauna with fresh air from the outside, and an out take vent also to the outside. The Russian banya style is a vent about bench high as well as a vent up towards the ceiling, allowing for infinite control of allowing air flow and steam to escape.

Controlling the Heat for Better Steam

Those familiar with saunas only in health clubs or hotels may wonder why there’s a dial on the sauna stove control panel. The dial is always cranked to the max. And often, it’s still not hot enough.

Secret: most commercial sauna stoves installed in the US have a “governor” on them. Safety first! It’s against the law to have a hot room hotter than 165 degrees f. Clever health club regulars try to work around this by tossing a little water on the control sensor “tricking” the sensor to think that the sauna hot room is cooler than it really is, so the controller tells the stove to “get going!”

Yet, often, even this trick doesn’t always get the sauna stove rocking. Poor stove. Cranking it out all day everyday, like the little engine who could, trying to heat the sauna rocks to foster an environment to produce good loyly (steam created from water being tossed on sauna rocks).

Sauna stoves in health clubs and hotels have other things to overcome, like:

  • hot room door opening and closing, extensively.
  • large hot rooms, often oversized, and the dreaded 8′ ceiling which contributes to lots of wasted cubic feet.
  • Meathead construction: not enough insulation and/or no vapor barrier behind the wood paneling.

The dials on sauna stove control panels for public saunas in the United States are mostly useless. Saunas in public places in the United States are subject to rules and regulations prohibiting hot room temperatures at 165 degrees f. So, you can crank the dial to 11, but the upper limit governor kicks in. Yes, you can toss some cold water on the temperature regulator up along the ceiling, and that’s the best you can do.

But we really aren’t in a position to throw these saunas under the bus. Health club and hotel saunas are wonderful gateway drugs for folks to build their own saunas, and enjoy an authentic sauna experience on their own properties. And yet many folks don’t own their own properties or can’t afford their own saunas. So we are presented with an “end around” evangelical effort to support and bring really awesome public sweat lodges to the forefront. Chicago Sweatlodge and Red Square (the former Division Street Bathhouse), and other saunas in the public domain make great heat.

Electric Sauna Heater Review by Professional Electrical Engineer

5/29/2017

Thank you to Jeff for this awesome content reviewing electric sauna stoves.

Electric Heater Variety

The variety of electric sauna heaters available in North America seems a bit overwhelming at first glance. There are at least ten different brands, each with several model lines. The manufacturer and retailer’s websites aren’t very helpful as they are dominated by marketing hype and claims of superiority without much substance. Most seem better at confusing rather than informing.

Where to Start?

The number of electric sauna stove choices seems overwhelming at first. Looks can be deceiving. I started compiling a spreadsheet to sort them out and quickly noticed a surprising amount of commonality. It turns out that most of the available family sauna units are different variations of the same basic wall-mounted design. This was surprising until I understood two things:

One, the US market is dominated by two big European manufacturers, Tylo-Helo and Harvia, and a couple of minor players. Much of the apparent variety comes from rebadging the same core design under different brand names.

And two, only the most common designs that are likely to sell well are certified for the North American market. Most of the minor European manufactures haven’t been certified in the US. In addition, the major manufacturers have only certified their most popular variants. This has resulted in a rather bland selection compared to that available in Europe.

The Finlandia FLB series (left) and the Harvia KIP series (right), both are manufactured by Harvia Oy in Finland and are the same unit with cosmetic changes. Think of the Chevy Camaro and the Pontiac Firebird and you’ll get the idea.

So remember that Finlandia and Harvia are the same. Amerec, Finnleo, Helo, and Polar all fall under the Tylo-Helo umbrella and are at best very similar using the same parts, with some models being rebadged units. Tylo, while being part of the Tylo-Helo umbrella, is a bit of an outlier as its models are unique. Of the North American manufacturers, Saunacore and Sauna Craft are the same and made in Canada. Scandia is a reputable US manufacturer, though its units look a bit too utilitarian for my tastes.

Chinese Brands

There are some Chinese and other off-brand units available that on the surface look to be bargains. I didn’t spend much time researching these and never seriously considered them. Sauna heaters by design generate high heat levels in a highly combustible environment. On top of that, they run relatively high voltage (240 Volts) through a metal box into which we dump water. They can outgas if not made of heat stable materials. Based on this, I only considered manufacturers with a long history of not burning down saunas, electrocuting or poisoning their customers. I’m not saying these off-brands are a risk, but I wanted to see some history before entrusting my family’s safety. Sort of like how no one wants to be a new surgeon’s first operation.

European market

After browsing through some European sauna store websites, one can’t help but become envious at the huge selection available to the European consumer. It is possible to buy from these sites and have the units shipped to the US. There are some real challenges and potential pitfalls in doing this, that we’ll discuss in part 2 regarding “gray-market” heaters.

The Harvia Globe is a cool-looking orb with a large exposed stone surface for loyly. Interested? Unfortunately it, along with a multitude of other unique designs, isn’t certified for North America. Most US units are the same bland wall-mounted box design.

Electric Sauna Heater Sizing

First thing to do is estimate the required heater size as it will drive all remaining decisions. These guidelines are from Harvia, but they’re sound and typical for the industry. Undersizing will cause real misery as the sauna will take an inordinate period to heat up if it ever gets there. Oversizing can be an issue also (though less of one IMO) as you don’t want the heater to feel like a blast furnace when it cycles on. Note that these guidelines assume a properly constructed and well-insulated sauna. These also assume a 7 foot maximum ceiling height as higher heights significantly increase heating requirements. If you go that route you are on your own. Round the final answer up rather than down to prevent undersizing.

  • Guideline 1: Allot 1 kW of heater power per 45 cubic feet of sauna interior volume
  • Guideline 2: For each non-insulated square meter (10.75 square feet) of wall surface, add 1.2 cubic meters (42 cubic feet) to the volume of the sauna. This would include walls made of rock or brick, and large windows.
  • Guideline 3: For outdoor saunas in very cold climates, consider bumping it up a size if your calculated value is close to the standard size

Example

  • 5’ x 7’ family sauna with a 7 foot ceiling ->5 x 7 x 7 = 245 cu ft (guideline 1)
  • 32” x 16” window -> (32 x 16)/144 = 3.55 sq ft / 10.75 = 0.33 sq meter. Thus 0.33 x 42 = additional 14 cu ft (guideline 2)
  • Total = 245 cu ft + 14 cu ft = 259 cubic feet -> 259/45 = 5.75 kW
  • Outdoors in a moderate climate -> no adjustment (guideline 3)

Thus we end up with a 5.75 kW need, bumped up to 6 kW or 6.8 kW as these are standard sizes depending upon the manufacturer. A typical family sauna usually will usually end up somewhere in the 5 to 8 kilowatt (kW) heater range.

Electrical Power Needs

Anything above 2 kW (suitable for only small 1-2 person saunas) will require a dedicated 240 Volt circuit wired directly from the electrical service panel. This might seem overly complicated but it really isn’t as all modern US homes have 240 Volts available even if it only has 120 Volt outlets and appliances.

(Standard disclaimer: These points are passed along to educate. If you don’t know what you are doing or aren’t willing to spend some serious time doing research first, hire a qualified electrician to do the actual work. The National Electric Code has specific requirements on wire size, wire type, conduit size, conduit depth, grounding, breaker sizing, and other odds and ends that must be followed to ensure a safe and compliant installation. Some of these requirements aren’t intuitive and your family’s safety is at stake. )

A quick assessment of the home’s electrical panel will let you know what sort of shape you are in. Look for three things:

  • The existing electrical service size in Amps – This can be found on the main breaker, usually labeled “MAIN” or “SERVICE DISCONNECT”.This will be a double breaker that is often larger in size than the others with typical values of 100, 125, 150, 200 Amps, or even higher.
  • The existence of other 240 Volt appliances – These will be double breakers that serve large appliances such as electric ranges or water heaters, or an air conditioning compressor.Look for anything marked 30 Amps or larger.
  • Spare spaces in the panel – Either spaces where the breakaway metal tabs have not been punched out or is filled with a plastic blank.

Typical service panel, the MAIN is at the top in this example and lists the Amp rating on the switch lever. Two 240 Volt branch circuits (double width) are present on the lower right. Plenty of spare spaces available here. A family sauna heater will typically need a new 30 or 40 Amp breaker/sizing depending on the kW rating. Generally, expect a 6 kW to need a new 30 Amp breaker, and 8 kW unit to need 40 Amps. The exact current draw can be calculated by:

Heater size in Watts / 240 Volts = Current draw in Amps

One kilowatt (kW) = 1000 Watts

Thus a 6 kW unit will draw 25 Amps, with wiring and breaker sized for 30 Amps, the next higher standard size.

If your existing service size is 150 Amps or higher you should be fine. You again should be fine if it’s smaller and you don’t have exiting 240 Volt appliances. If it’s small and you do have existing 240 Volt circuits you will need to do a little more research.

As an example, an older home with a 100 Amp service with air conditioning, an electric water heater, and a new sauna heater all running at the same time could exceed the 100 Amp service. This isn’t dangerous as the breaker will trip and protect the home (assuming it’s in good working order). It will be extremely annoying though, particularly when one is trying to unwind in the sauna after a long day.

If you fall into this camp, a qualified electrician should perform a load assessment before going further. It is not as simple as adding up the breaker totals as no one uses all branch circuits to capacity at the same time. It’s a statistical analysis that determines the highest load the service will likely encounter in daily usage. If the load calculation exceeds your existing service level, it might be worthwhile to upgrade your service panel and feeder lines. Be prepared to spend several thousand dollars. Hopefully not required but do your research first rather than realize the need after you’re in the dark.

Next Step

Assuming we’ve cleared that hurdle, next check to ensure you have two adjacent spare spaces in the panel. They must be adjacent as a double breaker is required with the trip levers tied together. If you have two but they aren’t adjacent, a competent individual can rearrange them in the panel to free up two next to each other. If you don’t have two, spaces can be opened up by using tandem (half size) breakers. Convert some of the existing 120 Volt circuits to tandems so you can use a full size double breaker for the new 240 Volt sauna circuit. Note that not all panels allow the installation of tandem breakers so don’t just assume this is feasible without checking first.

If you’ve made it this far, it’s time to start drilling down into the available heaters.

Built in Controls vs. Remotes

The next major decision point is the heater controls. The lowest cost models simply incorporate the controls into the heater itself, usually two knobs located at the bottom of the unit. There’s a temperature knob and a time knob, all one really needs to enjoy a good sauna. Simple, straight-forward, functional, and relatively inexpensive.

Personally, I was looking for something a bit more sophisticated and I also wanted the controls outside the sauna itself since I have small kids and didn’t want them monkeying with them. There are manual remote controls that do little more than move these knobs outside the sauna, perhaps with a coarse time delay knob added on for some additional convenience. These will add one or two hundred dollars in cost and I’m not quite sure I get it. To me these look like they belong in a gym or a hotel fitness room and they also make an annoying ticking sound. To each their own.

Step 2

The next step up is a full digital control that allows programming the specific temperature, sauna time, and delayed start. It also incorporates sauna lighting and an optional exhaust fan control. Further, the control can be programmed to automatically start and end a drying cycle and activate the exhaust fan and the end of the sauna session. There are also a few other customizable settings in the controls. It includes a digital temperature readout much like a home thermostat.

These controls are typically an add-on and the prices can cause sticker shock being upwards of $500. While they aren’t cheap, they aren’t quite the overpriced rip-off they might seem to be on first glance. Remember that the cost of the heater itself will be cheaper without the built-in controls, usually on the order of $100 or more. Also, most of these digital controls will typically move all the electronics except the heater elements and temperature sensors outside the hot room into a separate, remote contactor box. This separate box is usually included in the remote control package price.

There is a real benefit in wear and tear in locating these parts in a room temperature environment. The remote box will typically include a circuit board with some sort of microcontroller and one or more heavy duty contactors (electrical relays). Electronics don’t like either heat or humidity, and are subject to early failure unless specifically designed and tested for such environments (i.e. military grade). In addition, these types of failures are often intermittent thus being difficult to troubleshoot. As the electronics are usually the most expensive components to replace, putting them outside the hot room makes good sense to prolong life.

Step 3

The next step up the line uses a wi-fi connection to allow turning the unit on/off from a distance further than feasible using a wired remote. The Tylo Sense Elite line incorporates this feature but be prepared to spend big bucks. Tylo states unequivocally that this feature is for turning on the unit from another location on your property. It specifically is not intended to turn on the unit from a location away from home. So don’t expect to turn it on from the office to have it ready when you get home.

Shop around as the control package price for the same unit can vary wildly among different distributors. (When comparing prices do make sure the controller model numbers are exactly the same as there are a variants that look the same but intended for different heater units.) Provided the controller is compatible with the heater, there is no reason you need to buy them from the same distributor if you find deals on each. If shopping online (E-bay in particular), do ensure that the controller is certified for the US market. European versions are configured to operate on different voltage forms and will not work on standard US 240 Volt single-phase power without significant modification.

Rock Cavity Design, Size, and Distribution

Rocks are essential for any sauna heater as they act as a heat sink, and thus allow soft steady heat over time. An analogy from other applications might be a reservoir at a hydro-electric power plant or a flywheel in an engine. Its purpose is to store energy and smooth out delivery A sauna heater without rocks would provide a blazingly hot blast when the heating elements cycled on and then the sauna would quickly cool when they cycled off. Ideally, there should be no noticeable temperature fluctuation during heater element cycling.

Amount of Rocks

So just as a large reservoir provides more steady and reliable hydro-electric power than small reservoir, does that mean the more rocks the better? To an extent, yes. There’s a point of diminishing return where more rocks makes no noticeable improvement in sauna temperature variations. More importantly, more rocks can significantly increase sauna warm-up time as the rocks heat up much slower than the surrounding air. A major selling point of an electric heater is their convenience. If it takes two hours to warm up the sauna then one may as well build a fire.

Of course the rocks are also the source of steam when water is thrown on them, aka loyly. More rocks are better here too as the heater can instantly convert more water to steam with less running through and ending up as a puddle on the floor. However if there are too many rocks for the heater size then the rocks might not get hot enough to make steam in the first place.

Rock Distribution

You probably get the picture that the rock configuration requires some compromises to balance these competing factors. Different compromises result in different heater performance. Unfortunately, 80 to 90% of the heaters certified for the US family sauna market use the same basic setup with the same compromises (unlike the European market). The standard is a wall-mounted unit, a fairly deep rock cavity, 45 lbs of rocks, and the rocks in direct contact with all heating elements. Most electric heater models are the sauna equivalent of the Toyota Camry, functional and pragmatic, they get the job done but aren’t very inspiring. Not only that, most are pretty drab in appearance, a real shame after all that work in building the sauna and hand selecting cedar boards.


Some Imaginative Designs Available in North America

There are some notable exceptions that show some imaginative engineering. Tylo heaters use side chambers where a large portion of the heating element only contacts air. Rocks are limited to the center cavity and are fewer in quantity than that of competing models. Some hold as little as 20 lbs of rocks. This results in fast sauna warm-up times.

You would think this approach would cause sharp heat and large temperature fluctuations but Tylo implemented a clever solution.Virtually all family sauna heaters use three heating elements that turn on and off together. Tylo, on the other hand, operates their heating elements in stages. Rather than turning on or off all three elements at once, it changes the number of active heating elements based on the desired temperature change. This helps smooth out temperatures over time despite the small rock quantity.

Free-standing Towers

There are also some family sauna free-standing towers that have been recently certified for North America including the Harvia Cilindro and the Finnleo Himalaya. These have huge rock capacity as they hold over 200 lbs. of stones. There is also plenty of exposed rock surface for throwing water thus creating strong bursts of loyly. These recent entries into the US market hopefully indicate we’ll soon see more true variety available to the US consumer.

We ended up selecting the Harvia Virta, another imaginative model recently certified for North America. The Virta is a floor standing unit that holds 110 pounds of rocks. It uses a clever cage to separate the rocks from the heating elements that Harvia claims will speed up warming time. We selected it based on its features and lots of good feedback and comments on European websites (thank you Google translate!) and we’ll post a report once we are up and running. Plus the unit is just stunningly beautiful to look at, using high quality polished stainless steel punctuated by crisp, straight lines.

When our unit arrived it was plastered with hideous orange and white warning stickers that assume the user is an imbecile. Not only that, they stop just short of telling you not to turn the unit on at all if you know what’s good for you. Somehow I doubt the units shipped within Finland end up like this. Fortunately they are removable and will be coming off ASAP.

Tylo Units are Genuinely Unique

I 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.

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 campfire 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.

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 than 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.

This isn’t meant as a 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.

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.

Nice Features of the Combi Unit

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.

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.

Gray-Market Electric Sauna 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:

Availability

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.

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 manufacturers 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 Gray Market Electric Sauna 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 won’t 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.

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.

74 thoughts on “Electric Sauna Heaters”

  1. i want with a tylo sport 8 kw unit, specifically because of the side air chambers and faster heating times, works great. in the winter time, only one element is necessary to keep the hot room hot once the rocks heat up. it will sometimes turn on the second element for a period if it is really cold (i.e. 10 degrees F or colder). one thing i would have changed was to get a remote contactor box. i don’t need all the wifi bells and whistles but having the electro-mechanical timer on the unit in the hot room leads to a ‘cbs 60 minutes’ effect, with a constant ticking. my hot room is insulated well enough that i can turn the whole thing off for the last round and sit in silence but it would be nice to be quiet the whole way through.

    strong consideration should be given to running a neutral to the sauna with the two hot 240v legs (and equipment grounding conductor) to allow for 120v loads (e.g. lighting and convenience receptacles). i have a detached sauna and put a subpanel in the changing room, with separate breakers for the heater, lighting and interior/exterior convenience receptacles. an outdoor receptacle is great for plugging in tools, a radio, etc.

    and as a point of clarification, the sauna heater circuit does not need to be served from the main service panel, a subpanel is totally acceptable. this is what i did with mine, i served the sauna from a subpanel i installed as part of my basement finishing project.

    also note that the nec is actually quite specific about how to calculate loads in sizing an electrical service. newer 200 amp services typically have no issue but may become a concern with older 100 amp services or really old 60 amp services.

  2. Hi Miller – Thanks for commenting, your post on building your own sauna (assuming it’s the same Miller) was a huge influence on my efforts. I can’t tell you how many times I’ve looked at the photos for hints.

    You are right about using a subpanel as the source if one’s available. I guess the bigger point I was trying to make is that it needs a dedicated breaker and can’t be “plugged in”. I completely agree also with running the neutral for accessories to have both 120/240 V. The Harvia I bought can control lighting and an exhaust fan from it so they recommend routing the neutral to the contactor box itself for this purpose too.

    The NEC does specify how to calculate loads but I didn’t think most casual readers are familiar with it or have a copy. There are also Excel spreadsheets available online if you google around a bit that incorporate all the NEC rules and allow a DIY load calc. I’m an EE (and I think you were too if I remember your post) so I’m comfortable doing it and did this for my house (100 Amp service). I’ve see some pretty scary homeowner wiring over the years so I didn’t want to encourage folks who aren’t versed in this to freelance in this area. That being said, if folks are sharp and willing to spend some time learning how to do it right then it’s certainly possible.

  3. jeff, can there be any other miller? 🙂

    i really need to get all my photos of my build up somewhere, i took hundreds. needed to trim it down to make a practical post but i’m sure i can figure something out to get them all up there.

    and i certainly wasn’t ragging on you with my previous comments, just trying to get info out there. electrical can be a daunting subject for the layman, best bet is to seek the advice of a professional rather than trust someone on the internet (even if they are a couple of rad EEs). local electricians are typically the best bet, they know the NEC as well as any amendments the local municipality may have adopted. if going the full permit route, they likely know the inspectors and how to work with them, a huge plus. engineers know a lot as well but let’s face it, we’re talking about a power drop to a sauna, not some high-end manufacturing facility or power plant…

  4. I’m loving reading these posts on electric heaters as I’ve been researching them as well.

    @miller – where can I find the write up on your sauna?

  5. Hi Miller – Just noticed you had replied. If you get a chance please do put your photos up somewhere and post a link as I’d love to see them. I’m really enjoying the engineering aspect of this whole project, particularly some of the minor details. My upper bench triangle brace went in last week and I’m pretty happy with how it came out, really compact size but solid as a rock. It’s one of those minor aspects that I probably thought about for a couple of weeks on and off since I wanted it to be bullet-proof. No one else will ever notice or care, but I’ll know it was done right! : )

  6. so i started a more detailed sauna build thread a few weeks ago:

    http://www.homebrewtalk.com/showthread.php?t=629337

    and of course, all the photos are hosted through photobucket. photobucket has recently changed its policies and it now costs $400/yr to hotlink from their site. check the news on it, quite the stink they have caused across the internet. writeup is sort of worthless without the photos but the easiest way i’ve found to see them is to use chrome. you can right-click on the photo placeholders and select ‘open image in new tab’. annoying, yes, but i am hoping photobucket changes its policies soon so i don’t have to host them somewhere else and re-build the entire thread.

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

  8. 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.

  9. 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.

  10. 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…

  11. 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

  12. 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

  13. Hi Miller – Checking back in after a bit of an absence. Thanks for posting these and the thread. Regarding photobucket I ditched it long ago as it’s just too much of a hassle. Plus I use an adblocker so it won’t even let me open the photos in a new tab without disabling it. Arrgh.

    I’ve got a wordpress.com free account for a blog on another topic. One of the nice things about is I can upload all sorts of photos to hidden pages on any subject then hotlink right to them. It’s a nice free alternative to photobucket and the others.

  14. 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.

    Thanks!

  15. 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.

  16. NEVER BUY FROM HARVIA

    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.

  17. This is such an incredibly helpful thread (along with Part II) – I cannot thank you guys enough for sharing this information. I am also in the process of planning for a backyard sauna in Southern California (a much more urban setting than your beautiful spot). But these articles have been invaluable as I query electricians.

    I did have a question about the sauna timers and “ticking” sound – specifically, did you find that all heater-mounted controls – which appear to be mechanical – make a ticking sound? I’m getting conflicting info from the dealers I’ve inquired with. I’m looking at the Camry-type heaters, and one dealer said the Polar HMR heater-mounted controls do NOT make any ticking because they’re electronic. Another website, which seems to have a Polar-looking variant, warns of a ticking sound with these dial-timers and recommends the digital control. Still a third place (local here) uses a proprietary branded Finnish heater (also looks like a Polar or the Harvia examples you posted) and assures me that normally no ticking is heard. And you mention there’s typically ticking. Did you find that one model/brand would typically tick vs others that might not?

    Ticking in the sauna would be terrible. I’d prefer to save $ and get a basic, heater-mounted control, but if there’s too much uncertainty I might just hedge my bets and spring for the digital control (in which case does one mount it inside or outside the sauna?) But would love to hear from you and other folks who have actually interacted with electric heater with dial controls (wall or heater-mounted).

    Thanks again! Hope to be sharing photos here one day – not too many outdoor saunas I’ve heard of in SoCal.

  18. The electricians can wager in with more details, but controls should never be inside the hot room. Outside, in changing room only. Only exception is a non Finnish culture authorized volume control module – for music – installed inside the wall, right about where your ankle touches while sitting on the lower bench. If inviting a Finn to sauna, start with volume all the way down and see if you can ease it up a bit. But go easy. No rock and roll. And we take no offense to silent saunas as this is how it has been done for centuries.

  19. Thanks, Glenn. How about light switches? Can those be inside the hot room? (We’re building a sauna with no changing room due to space constraints and SoCal weather – no double-door grocery stores here! 🙂 )

  20. i can’t say i’ve seen every electric heater out there but all the ones i have seen with built-in controls utilize an electro-mechanical timer (complete with clicking sound). these are rugged devices suitable for the hot room environment, as opposed to the ‘fancier’ digital controllers with touchscreens, wifi interface, etc. i have built-in controls and honestly, you get used to the ticking and don’t even notice it after a while. if you want the separate controller, consider the installation environment if you don’t have a changing room. if outdoors, is it protected from the rain? protected from direct sunlight? keep those items in mind, might want to have a little canopy or something to place the controls under.

    similar for a light switch in the hot room. a ‘regular’ switch at the typical mounting height will not fare well. you could mount it low to the floor but now you run the risk of splashing water getting into it, bending over to operate it, etc. better to have an outdoor-rated switch on the exterior. my friend in seattle doesn’t have a changing room and uses an outdoor-rated light switch on the exterior, works great.

  21. Maya: I would put your light switch on a dimmer rated for outdoor use, on the outside wall. Glad you read about my double door grocery store observation! you get it!. (and So Cal weather is an entirely different story!).

  22. 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.

  23. 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.

  24. Has anyone bought and used a real full-sized electrical stove furnace for Russian sauna? I can’t find any online in the US.

  25. 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.

  26. My issue was inconsistent heat due to the on/off of the element. Now back to a wood stove for constant heat.

  27. Kev Connell I feel like this was written about me, particularly with the Chicago Sweatlodge reference! I love wood burning saunas but do not currently own one. Here are some helpful tips for sauna lovers who use health club saunas. 1- Use very cold ice water if you do the thermostat trick! it kicks the heater in quicker and longer. 2- When you use the water on thermostat do it 15-20 minutes before you sauna to pre-heat the room and rocks. 3- Speaking of rocks I lobbied my club for newer and additional rocks in the stove I even provided an Amazon link in my e-mail. (for a club with a multi million budget $50-$75.00 for some rocks is pretty minor) 4-If they are really strict about water on the rocks use some water on the benches and walls it has several benefits( it provides moisture/heat to the air, it often accentuates the cedar smell, and it cleans the benches. 5- If there is a thermometer in the room sprinkle a tiny amount of water on it to keep it showing 160-180. I have found people will immediately complain to mgt.or freak out if they see 200 plus. 6-Educate the others (particularly if there are regulars) I have solved the heat issue for the most part at my club, I can get 200 plus temps in a very short time I have not completely solved the cold plunge yet. I use cold showers and pool (usually not cold enough) Fortunately when the temp outside dips below zero I have access to go outside onto the outdoor pool deck to chill. Thanks for the article Glenn Auerbach!!

  28. 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!.

  29. 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!

  30. 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!

  31. 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.

    Thanks.

  32. 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?

    Thanks!

  33. 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!

  34. 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.

  35. Hi Glenn,

    I just recently started looking around for information on saunas and I’m so glad that I came across your site, what a great resource!

    A question about the rock quantity. As discussed here, I understand that more is generally better, up to a point. I’m planning to build a small basement sauna and I am considering the Harvia Virta (~100 lbs capacity) or the Cilindro (~200 lbs capacity). The specs from Harvia indicate that the heat up time for either model, both at 6.8kW, is 1 hour (somehow they are the same?). I’m hoping to keep the heat up time down since I’ll be using the sauna for 30 minutes per session and don’t want to have it heating up for 2 hours every time.
    Would you recommend the Cilindro? Or would the Virta at 100lbs of rocks be more than enough for a small sauna, about 250 cubic feet?

    Thanks!
    Martin

  36. Martin:

    This is all good talk. Let me share a dirty secret: Amount of sauna rocks is not a reflection or guarantee of lampomassa and/or “ahhhhh” that is achieved either whilst sitting on the upper bench or via tossing water on the rocks.

    Some sauna rocks, especially down low, surrounding these electric heaters do not produce heat or steam. They are mainly cosmetic. I know this is a buzz kill, and all I can say is that Jeff, who wrote this article, is my go to source for electric sauna heater info. May the sauna gods bless him for his awesome work!

  37. Jeff:

    How has the Harvia Hirta Combi worked out for you. Would you do it again. Are you able to ventilate the sauna enough that the wood is in good shape a few years later?

    This would be great info as I am also interested in this model.

    R

  38. Hi Jeff, I’ve been researching electric stoves for my to be built 7x7x8 sauna including 2 windows and a 1/2 window/door. Using your formula I’m coming up with 9.3 kw + 1 would be 10kw. The sauna will be in a building, well insulated, but with no heat. I’m starting to narrow my choices to the Harvia Virta and was toying with the idea of the Harvia Combi. I’d appreciate your thoughts and recommendations if you wouldn’t mind—as well as any other electric stove options. I’m located in Northern Minnesota (Lake Vermilion). Thank you for all of the great information you’ve been so kind to provide. (this will be my 3 rd sauna—1 wood by the lake and 2 electric inside two different buildings—can you tell I love saunas!!!)
    TP

  39. After reading this thread several times I am not sure the question regarding the Harvia heater was ever answered. Did I miss it? Is there an opinion on either those mentioned above or
    the cilindro? Thanks for expert insights. 🙂

  40. Glenn wrote, “Some sauna rocks, especially down low, surrounding these electric heaters do not produce heat or steam.”

    I talk about this in the article and agree. If there are too many rocks for the heating element the rocks won’t get hot enough to make steam, only those directly in contact with the element will. Like Glenn said, they are there for show.

    After three years with the Virta I probably sound like a shill but I think it’s about the perfect balance. It has 110 pounds of rocks with a 6.8 kW heater and none of them are for looks (most are hidden inside the cavity surrounding the elements). My test is when you dump a large coffee mug of water on it at once, how much water ends up on the floor? Amazingly with the Virta it’s none, it all instantly vaporizes. My humidity meter in the sauna goes from much less than 20% to over 50% in seconds. It’s pretty intense. Too intense sometimes if the room is already really hot.

    Plus it heats up the room to temp in about 30 minutes which is great (albiet this is So Cal not Northern MN), but too many rocks will slow that down. Like I say in the article, it’s a balancing act. Hopefully the article didn’t come across as saying “the more rocks the better” as that’s not what I intended. You need enough rocks to soften the heat and prevent the toaster oven effect but beyond that can do more harm than good.

    Glenn – I think I may have had a comment get stuck in your spam filter regarding ventilation as it isn’t showing up.

  41. 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.

  42. I have a 6.8K Virta (without stream option) – much thanks to Jeff C for his thorough, insightful analysis- and have had the same experience regarding good Loyly , 0 moisture under the stove (after repeated dousings) and not feeling the ‘toaster’ effect, especially if it’s been on long enough (>1 hour) for heat to soak into the benches, etc…

    Moisture (basement sauna) has not been an issue at all. I do follow Glen’s ‘bake and breathe’ guideline. After my last round, I turn the temp up as high as it goes for 1 more hour, close the vents and keep a nearby bathroom vent fan on for 15 min. The next day, when I open the door / vents, the hot room temp is still 90+F and is bone dry.

    I’ve heard great things about the Himalaya first-hand from a local Finnish-born sauna expert who’s had his for several years. I don’t think you can go wrong with either the Virta or the Himalaya. If you can’t decide between the two, perhaps consider proximity to who you’d buy it from for purposes of support/convenience. Post-covid, I think I will try weasel into a session at the Himayala sauna to see how the Virta stacks-up and post here again with my observations.

    My sauna experiences in Northern MN / WI / MI have shown me that no electric sauna can hold a candle to a properly built wood-fired sauna. That being said, my electric Virta sauna built to Glen’s eBook and height/vent post-Finland trip blog entry specifications is by far the best electric sauna I’ve experienced, as well as better than many poorly-designed wood-fired saunas I’ve experienced. The stove is critical, but can be hindered by a sub-optimal hot room (venting, bench height, etc…). Luckily, this kicka$$ site, its founder and its community help amateurs like me, make the most of my stove.

  43. Agree Nic, the Virta is a great electric heater. Never used a Himilaya but I’ve heard good things. Also agree with your comments about a wood stove being best but a well-designed sauna with a great electric heater is awfully good.

    Ventilation really can be the difference between a good sauna and a great sauna IMO. After Glenn’s trip to Finland and the things he learned about venting I modified my sauna and it made a big difference. It was good before, now it’s perfect. Mine is an outdoor sauna with a changing room. My intake was a gap under the sauna door and the outlet was an adjustable vent under the upper bench.

    It worked pretty well most of the time except when it was windy outside. Since the intake was indoors (to the changing room) and the outlet was outdoors, wind outside would foul up the pressure differential and it wouldn’t flow at all. Sometime it would even flow backwards as I could feel air coming in the outlet. For proper ventilation the intake and outlet must vent to the same space (i.e same room for both indoors or both outdoors). I had read this but thought as long as I vented the changing room to outdoors it would still work. It sort of did but not good enough for me.

    I added an always-open intake to the outdoors next to the bottom of the heater. I also added an adjustable vent at the top of the sauna as an outlet. I now have two adjustable outlets, one mid height (under upper bench) and one high (at the ceiling). By adjusting the flow between these two I can change the temperature profile from the floor to the ceiling. Using the top vent only makes a big temp gradient as the floor is much cooler (good for when kids are in the sauna). Using the mid vent only makes the temp more even which is nice when sitting on the top bench (feet are still hot). Combining them can dial in most any temp profile.

    If building a sauna from scratch people might want to consider this as the cost is negligible but it adds great flexibility.

  44. 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.

  45. 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.

  46. 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.

  47. 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.”

  48. Hi there,

    I’ve recently purchased and reassembled a custom built sauna from a friend I’m my garage. It uses a Nature NTSB 60 electric rock heater. I had it up and running well but decided to re-install the temperature gage to a different area and as I was reinstalling it I created a short in the junction box and seem to have fried an important part of the electronics. The friend I purchased it from has no information about where to get replacement parts and I can’t find any information about the company itself. Would it be possible to chat via email? Any help would be so greatly appreciated thanks!

  49. Darin:
    I’m not familiar with this unit. Hopefully someone else is on here, and can advise. I take it you tried contacting the mfr. That’s all I can suggest.

  50. 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.

  51. I’ve read several recommendations on trying to design your sauna so that when sitting on the top bench at 36″ in height, your feet should be level with or higher than the top of the heater rocks, Since typical lower bench height is 18″ and the 6.8K Virta is 32.4″ high, does anyone have cold feet?

  52. 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.

  53. 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.

    Thanks,
    Dave

  54. I’ve got a question for Jeff regarding Grey Market Electric Heaters: I’ve been obsessing over getting something as close to wood burning as I can (I’m in California in an urban area, and this will be under my carport). I’m intrigued by the Virta and Himalaya and Cilandro, but found 2 other cool international ones: Huum and Saunum.

    Huum

    https://huumsauna.com/

    is a massive amount of rock with a cool external control. Saunum

    https://saunum.com/

    has a venting thing where it distributes temp and steam throughout sauna, which claims to even temp of benches and give a better sweat and softer sauna. What is your opinion on this, Glenn and Jeff? Seems like you wouldn’t get a break on the lower bench, but, perhaps you wouldn’t need one if the heat was so balanced.

    And Jeff, my main question: If I get this internationally, how hard would it be to wire it up to a 240 V? It’s Estonian made. I’m in contact with manufacturer, but curious what you think. I’m just so bored of the sturdy but bland American heaters and want something that adds value to something I’m already spending 8k on.

  55. 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.

  56. Hi, Everyone!
    I know that HUUM has SGS certifications for many of its heaters for the US market. So, they are easy to install and safe to use.

  57. For sure, Teet, but importantly, and hopefully soon , Huum heaters will achieve UL 875 certification. And the controller UL353 and Ul873. It’s a litigious minefield over here in US!

  58. 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?).

  59. 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

  60. Hi Glen and Jeff,

    Great article! Thank you for all the info. Quick question for Jeff. Based on this article I decided to go with a Virta Combi heater for my sauna, but I am a little worried about the extra humidity. Jeff you mentioned that you are using an exhaust fan. What kind of a fan are you using that is able to withstand the high temps of a sauna?

    Thank you

  61. Hi Glen,

    You recommended the IKI Pillar electric sauna heater on your home page. Can you point us to where you recommend we buy these in the U.S.?

    Thanks!

    Robert

  62. Hi Robert, at this stage of the game, I recommend hanging tight for a couple of months, if you can. I’ll shoot you an email. Hashtag: Safety first. UL Certification molasses.

  63. We are installing a shower in our basement sauna and going back and forth about installing an electric vent to pull moisture out post shower. Is there even a vent that could be used in higher temperatures?
    Best,
    Aliina

  64. Aliina:

    If you’re looking for someone to break the tie, I vote mechanical vent to pull moisture out of your sauna. But, my vote comes with a major bold asterisk *

    I suggest you do not install a shower in your hot room. Reasons? Let’s list two of them.
    1. Wood paneling (like cedar) can take moisture, but not the prolonged wetness from running/splashing water from a shower.
    2. A sauna heater (even 100% stainless steel) can take moisture, but not the prolonged wetness from running/splashing water from a shower. your electrical components will not hold up, and you may want to check, but I think your heater warranty will be void if you install a shower in your hot room.

    Even the bake and breathe method will become a little engine that can’t.

    Sure, some saunas at cottages and cabins have showers in the hot room, but installing a shower in the hot room for your basement electro sauna is a bad road to go down. You are going to build this sauna one time. My strong suggestions is:
    1. Build your sauna in your basement.
    2. Install a separate shower outside your sauna in your basement.
    3. Vent your shower stall with a mechanical vent.
    4. Vent your hot room per instructions from your sauna heater manual.

    The combination of #1-#4 will put you in a place where you’ll come back one day and say something along the lines of “Damn, that SaunaTimes guy was right. He must have been studying the nuances of sauna for a long time, and probably has been taking saunas for several decades now. He really understands all this stuff. Phew, i’m glad I found SaunaTimes and digested all this free relevant information.

    After all this, if you’re still thinking of installing a shower in the hot room, keep in mind that no sauna I have ever seen in Finland has a shower in the hot room. Yes, I know it exists, and yes, the sauna cognition theory may support one’s passionate defense of shower in the hot room, but I’m not taking the bait. You’ll be miles happier in the long run with a shower just outside your hot room.

    But if not, something to think about is that you may be better off a with a steam shower instead of a sauna.

  65. Glen,
    You spoke directly to all of my concerns, thank you! No shower in the sauna!
    Aliina

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