Electric Sauna Heaters

Electric sauna heaters for sale here run from 3.5 to 16 kW, in wall, pillar, floor-standing and combination formats, all factory-authorized. The orders that go wrong are almost always the ones where the supply was assumed rather than checked. Find out whether your panel is 240 volt single phase or 208 volt three phase, then call (888) 500-5675 and we'll tell you the output, the amperage and the circuit.

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Electric Sauna Heaters: What Decides Which One You Need

Forty pounds of rock gives you a sharp burst that fades before you've put the ladle down. Three hundred pounds gives you a wave that keeps arriving. Same nine kilowatts, same electricity bill, completely different room.

That's the part nobody compares. Everything else on this page is the part your electrician cares about, and it's worth getting right first, because it's the one that can stop an order dead.

The range runs from small units under two kilowatts for a converted closet up to twenty and beyond for commercial rooms. Room-volume sizing, stone capacity and running cost are all covered on the sauna heaters hub. Most of the market sits at six, eight and nine kilowatts, which covers home saunas built for two to six people.

Electric pillar sauna heater with stones in a glass-fronted sauna room

Mounting

Wall-Mounted, Pillar or Floor-Standing

Four formats, and the one that decides how the steam feels.

Wall-mounted

Bolted to the wall so the floor stays clear, which matters in a small room. Generally the simplest to install and the least expensive at a given output. Stone capacity is modest, so the steam is sharper and the room cools faster between ladles.

Pillar

A vertical column with elements running through the stone rather than under it. Holds far more rock, which gives a softer, longer steam and a more even room. Takes floor space and usually costs more. This is what people upgrade to when they care about the bathing.

Floor-standing basket

Larger capacity units for big rooms and commercial installations. High stone mass, high output, frequently specified on three-phase power. Needs clearance on all sides and a guard rail.

Harvia wall-mounted electric sauna heater beside a bench in a small sauna room
Wall-mounted: the floor stays clear, which is what decides it in a small room.

A fourth format, the combination heater, carries a small water reservoir. Electrically it behaves like any other heater of its output, so everything on this page applies to it unchanged. What it does to the room is covered under stone capacity on the hub.

This page stays on the electrical side. If there is no practical way to run a heavy circuit to the room, look at wood-burning sauna stoves instead.

The electrical spec

Amperage, Wire Size and How Many Circuits

Published manufacturer figures at 240 volts single phase, and the threshold where a second circuit actually becomes necessary.

Almost everything a home buyer will look at runs on one circuit. The idea that a nine or a ten and a half kilowatt heater needs two feeds is common and wrong, and it's contradicted by the manufacturers' own tables.

Swipe the table to see every column.

Output Rated amperage Min. 90°C copper Circuits
3.5 kW 14.4 A 14 AWG One
4.5 kW 18.8 A 10 AWG One
6 kW 25 A 10 to 12 AWG One
8 kW 33.4 A 8 AWG One
9 kW 37.5 A 8 AWG One
10.5 kW 43.75 A 6 AWG One
12 to 15 kW 50 to 61.7 A 4 to 6 AWG Two
16 kW 66.7 A total 8 AWG per circuit Two or four

These are the manufacturers' published rated amperages and minimum conductor sizes, not breaker sizes. One major manufacturer publishes amperage only and leaves overcurrent protection to the installer; another publishes a breaker column alongside it. Your electrician sizes the breaker to the code edition your jurisdiction has actually adopted, and fixed electric heating counts as a continuous load, which means both the conductor and the overcurrent device are chosen with headroom over the figure in this table rather than matched to it.

Where the second circuit really starts

The code rule people are half-remembering is element subdivision. Above forty-eight amperes of element load, the elements have to be subdivided, each subdivided load kept under forty-eight amperes and protected at no more than sixty. At 240 volts that threshold lands around eleven and a half kilowatts.

Two things follow, and both get garbled in retail copy. Subdivision is done with supplementary fuses fitted inside the heater at the factory, so it doesn't by itself mean two feeds from your panel. And separately, some large heaters genuinely do want two supply circuits, which is a manufacturer instruction rather than a code rule. In practice, one circuit carries you to around ten and a half or eleven kilowatts. Twelve and above is where a second feed, or a small subpanel, starts appearing in the install manuals.

Ask before you choose between a 10.5 and a 15. That step is where the wiring cost changes, and it's usually a bigger number than the price difference between the two heaters. It's worth a phone call before you order rather than a conversation with your electrician afterwards.

Voltage and phase

240 Volt, 208 Volt, Single Phase and Three Phase

The single most common reason an order gets returned.

What you probably have at home

Domestic supply in North America is 240 volt single phase, the same service an electric range or clothes dryer uses. Virtually every residential sauna heater is built for it.

What commercial buildings often have

Office buildings, gyms, hotels and apartment blocks frequently run 208 volt three phase instead. The same heater on 208 volts does not produce the output it does on 240, and manufacturers publish separate part numbers and separate ratings for each. An eight kilowatt heater that draws 33.4 amps on 240 volt single phase draws 22.2 amps on 208 volt three phase, across three conductors instead of two.

Ordering the wrong one means a heavy freight return and a delay measured in weeks. Confirm what is actually at the panel rather than assuming from the building type, and if you're specifying for a gym or a hotel, see commercial saunas for rooms built around these heaters.

Floor-standing commercial sauna heater with a stone basket
Floor-standing commercial units are where 208 volt three phase turns up most often.

Inside the room

Cable run within sauna walls has to be rated for the temperature it will see. The North American manuals for these heaters call for 90 degree Celsius copper run in sealed flexible conduit from the wall to the heater, with a connector rated to the same temperature, and they're explicit that plugs and pigtails are not permitted inside the sauna room. Receptacles and switches stay outside.

If you've read that these heaters require a particular European rubber cable type, or that PVC insulation is forbidden, that's from the European manual for the same product. The North American manuals specify a temperature rating and conduit instead. Follow the manual that shipped with your heater.

The conflict

GFCI Breakers: Manufacturers and Local Code Disagree

Nobody in this category requires one. Most tell you not to fit one. Your inspector may say otherwise.

This is a genuine and unresolved conflict, and it catches people at inspection rather than at purchase. The manufacturers' positions range from a flat prohibition to a soft recommendation, and only one of them explains why.

What the manuals say

Most say plainly not to connect the heater through a ground fault interrupter. One goes further and states that if the heater is connected to a GFI breaker, nuisance tripping may cause unnecessary wear on internal components and the warranty on those components is voided. Another manufacturer merely recommends against it and gives no reason. A fourth says a GFCI is not required by the electrical code, and to fit one only where local code demands it, while warning it will cause nuisance trips.

What your inspector may say

Local code may require GFCI protection regardless, and that becomes more likely for an outdoor sauna or one in a wet location. Where the two positions collide, the inspector decides, and the manufacturer's warranty position doesn't change that.

Raise this with your electrician before the rough-in, not at inspection. If your jurisdiction requires GFCI protection on this circuit, you want that known while the wiring is still open and while there's still time to ask the manufacturer where it leaves your warranty. Call (888) 500-5675 and we'll tell you the published position for the specific heater you're considering.

Controls

On-Board Controls or a Wall-Mounted Control Unit

Two ways to switch a heater on, and one of them has a capacity ceiling worth knowing about.

Some heaters carry the timer and thermostat on the body. Others expect a control unit mounted outside the hot room, bought separately and wired separately. Manufacturers signal which is which in the model code, but conventions differ between product families, so confirm rather than infer.

Controls on the heater

Cheaper, simpler, nothing extra on the wall. Fine for a home sauna you walk into and switch on. Two limitations: you have to be in front of it to start it, and on-board controls tend to top out around eight kilowatts, so the largest heaters don't offer them at all.

Separate control unit

An additional purchase and a position to plan, but it brings a start timer, a proper display and, on current units, app or Wi-Fi starting. Combination models, which add steam on top of the dry heat, sit in hybrid saunas. If you want the room hot when you get home, this is what does it. Each control unit has a published maximum load, so it has to be matched to the heater rather than chosen on features.

Matching the control to the heater

Control units publish a maximum load, and it is lower than people assume. One common wall control is rated to 7 kilowatts on a single supply circuit and 12.5 across two; its higher-capacity sibling reaches 10.5 and 15. A control that ran your old 6 kilowatt heater may not be rated for the 9 you are replacing it with. Check the pairing rather than reusing on faith.

There are also code requirements covering timer run time, where the control is mounted and a room temperature cap, and they apply to domestic saunas rather than only commercial ones. Those are set out under code and clearances on the hub.

What arrives

What's in the Box, and What You Still Need

Three things that are almost never included, and all three hold up an install.

Stones

Sold separately on essentially every electric heater. Quantity is set by the model, not the room, and runs from one box to six. The wrong stones can void the warranty, so buy stones sold for sauna use.

Control unit

If the heater doesn't carry controls on the body, the control is a separate part number with its own load rating. It has to be matched to the heater.

Guard rail

Required by the residential and mechanical codes, and described as necessary for safety in the manufacturers' own manuals. Most makers sell one built for their heater.

Ask us to quote all of it on one order. A heater that arrives without stones, without its control unit or without the rail is a heater that sits in the garage until the second delivery, and freight on a second shipment is rarely trivial.

Who buys these

What the Electrical Side Looks Like in Three Jobs

Swapping into an existing circuit

The supply already exists, which narrows the choice usefully and caps it. Match the existing output and supply first, then check whether your old control unit is compatible before assuming you can keep it. The clearances of the new model matter more than people expect in a room already built around the old one.

Building a new room

You have the most freedom here and the most to get wrong. Decide the heater before the walls close, because the circuit, the control position and the conduit run are all cheaper now than later. This is also the moment to settle ventilation. Most of these go into indoor saunas.

Gym, spa or hotel

Check the panel for 208 volt three phase before anything else. Duty cycle is far higher than at home, so stone mass and build quality matter more, and the timer and control placement requirements are enforced. We quote these through commercial sales.

Staff picks

Three Electric Heaters We Recommend Most Often

One for each of the situations above.

Straight replacement

Harvia KIP

The workhorse wall heater, available with controls built into the body up to eight kilowatts. Published at 25 amps for the 6 kW and 33.3 amps for the 8 kW, both on a single 240 volt circuit. The simplest like-for-like swap in the range.

See the KIP range

Best steam

Harvia Cilindro

The pillar format, with elements running through the stone rather than under it. Holds several times the rock of a wall heater at the same output, which is the difference you feel on the bench. One circuit up to 10.5 kW.

See the Cilindro range

Commercial, three phase

Harvia Club

Built for gyms, spas and hotels, with 208 volt three phase versions and outputs to 14.8 kW. The 15 kW build routes through a small subpanel rather than a single feed, so bring your electrician into the specification early.

See the Club range

All three are Harvia, because that's the electric range we carry. See the full lineup, including combination heaters and control units, on the Harvia page.

Before you order

Seven Checks Before You Order an Electric Heater

Every one of these is easier to settle now than after the crate arrives.

  • Room volume in cubic feet, not floor area.
  • Square footage of glass, tile or bare concrete, with the adjustment added.
  • Supply confirmed at the panel: 240V single phase, or 208V three phase.
  • Panel capacity, and whether the model wants one circuit or two.
  • Whether you want remote or app starting, which decides the control unit.
  • Stone quantity for that specific model, ordered at the same time.
  • Published clearances checked against where the heater will actually sit.

Clearances are the check people skip, and they are model-specific rather than general. The gap a wall heater needs above it is not the gap a pillar heater needs around it, and an inspector can fail an install that ignores either.

Questions answered

Electric Sauna Heaters: Frequently Asked Questions

Does an electric sauna heater need its own circuit?

Yes, a dedicated hardwired circuit. Most home-sized heaters run on one. At 240 volts single phase the published figures are 25 amps for a 6 kW, 33.4 for an 8 kW, 37.5 for a 9 kW and 43.75 for a 10.5 kW, all on a single circuit. A second circuit generally starts around 12 kW and above.

Do 9 kW and 10.5 kW heaters need two circuits?

No. That claim is common and the manufacturers' own tables contradict it. Both run on one 240 volt circuit, at 37.5 and 43.75 amps respectively. The code rule people are thinking of is element subdivision, which applies above 48 amperes of element load, around 11.5 kilowatts at 240 volts, and it's handled by fuses fitted inside the heater at the factory rather than by a second feed from your panel.

What size wire does a sauna heater need?

The North American manuals publish a minimum 90 degree Celsius copper conductor size: 14 AWG at 3.5 kW, 10 AWG at 4.5 and 6 kW, 8 AWG at 8 and 9 kW, and 6 AWG at 10.5 kW. Cable inside sauna walls has to carry that temperature rating and run in sealed flexible conduit, and plugs are not permitted inside the sauna room. Your electrician sizes the breaker.

What is the difference between 240V and 208V models?

240 volt single phase is standard domestic supply. 208 volt three phase is common in commercial buildings. The same heater produces different output on each, and manufacturers publish separate part numbers for each, so confirm what is at the panel before ordering. An 8 kW drawing 33.4 amps at 240 single phase draws 22.2 amps at 208 three phase.

Do electric sauna heaters need a GFCI breaker?

No manufacturer in this category requires one and most advise against it, because nuisance tripping is common on this kind of load. One manufacturer states that connecting its heater to a GFI breaker voids the warranty on internal components. Local code may still require GFCI protection, particularly outdoors or in a wet location, and where the two conflict your inspector decides. Settle it before the rough-in.

Can I install an electric sauna heater myself?

No. These are hardwired appliances, and both major manufacturers in this range make installation by a licensed electrician a warranty condition that requires documented proof, not just a statement that it was done properly. Cable inside sauna walls also has to be rated for the temperatures involved.

Do I need a separate control unit?

It depends on the model. Some carry controls on the body, which is simpler and cheaper, though on-board controls generally top out around eight kilowatts. Others need a wall-mounted unit, which costs more but gives you a start timer and app control. Each control unit has a maximum load rating and has to be matched to the heater.

Can I keep my old control unit when I replace the heater?

Sometimes, but check before you assume. Each control unit has a published maximum load, so a larger replacement heater can outgrow a control that worked fine with the old one. Pin compatibility and sensor type also changed across product generations. Give us the model number on the old control and the heater you are considering and we will tell you whether it carries over.

Does a combi heater need different wiring?

No. Electrically it is the same appliance as any other heater of its output, on the same amperage, conductor size and circuit count shown in the table above. The reservoir is filled by hand or plumbed depending on the model, and a plumbed one adds a water connection that has to be planned with the room rather than added later.

Where should the heater go in the room?

Follow the published clearances for the model, which differ between wall-mounted and floor-standing units and are part of what the heater was listed against. A corner is often the most efficient use of a small room, but only if the side clearances allow it, and the guard rail needs its space too.

Related

Browse Other Categories

All sauna heatersSizing, stones and running cost Wood-burning stovesNo circuit needed HarviaThe full range from one manufacturer Traditional saunasRooms built for a stone heater

Sauna use carries risks for some people. Read our full Medical Disclaimer.

Tell us the room and the supply

Dimensions, wall build, how much glass, and whether your panel is single or three phase. We'll tell you the output, the amperage, the circuit requirement and how many boxes of stone to order with it.

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