So you’ve found the perfect sauna heater and you’re ready to get started reaping all the benefits this form of self-care has to offer. There’s just one thing left to do - navigate the complexities of sauna heater wiring.

We want to be clear in saying that the average person should probably not try to learn how to wire a sauna heater and handle this task themselves. Electrical fires, shock hazards, voided warranties, and code violations are all risks that come with improperly wiring a sauna heater. 

It’s worth paying a professional to handle this just for the peace of mind alone. Nevertheless, we’ll walk you through how to install a sauna heater below so you can at least get a sense of what goes into this process.

If you haven’t already ordered your sauna heater, though, look no further than Nordica Sauna. We stock all the best sauna brands at the lowest prices, guaranteed. Get in touch today for a personalized recommendation! 

Otherwise, let’s start with an overview of wire gauges.

What Gauge Wire for Sauna Heater Do You Need?

Properly wiring a sauna heater impacts safety and performance, and it all begins with selecting the right wires for the job. If your sauna heater didn’t come with all the necessary wiring you’ll need to do some due diligence and find the right size and style.

What matters most is wire gauge, which speaks to the thickness or diameter of an electrical wire, measured using the American Wire Gauge (AWG) system. The lower the number, the the thicker the wire. 

This can be counterintuitive to some since bigger numbers correlate to bigger sizes in most other systems. Here, though, an 8 AWG wire is thicker and can handle more current than a 12 AWG wire.

This matters because thicker wires (lower gauge) is capable of carrying higher electrical loads without overheating. Saunas draw quite a bit of power to heat up, often between 15 to 60 amps depending on the model. So what gauge wire for sauna heater do you need? 

Factors That Influence Wire Gauge Selection

Just as with choosing the right heater size for your sauna dimensions, there’s no one-size-fits-all answer to sauna heater wiring requirements. You need to account for the following factors:

• Heater Wattage and Amperage Draw: Higher-wattage sauna heaters draw more current (amps). Check the model’s specifications for the exact amperage required.
• Voltage Rating (120V vs 240V): Sauna heaters typically run on 240 volts for the most efficient heating. Higher voltage calls for thicker wire to safely handle the increased load.
• Distance from Power Source (Voltage Drop): The longer the wire run, the greater the potential for voltage drop - which is basically a reduction in power as electricity travels through the wire. You may need a thicker wire for saunas located far from the main electrical panel to compensate for this drop.
• Single-Phase vs Three-Phase Power: Residential saunas usually operate on single-phase power, while commercial setups may use three-phase systems. This can affect wire gauge requirements, but don’t worry about it for home sauna installations.
• Local Electrical Codes: Local building codes and regulations always take precedence over other factors. Some jurisdictions might have their own specific requirements for sauna heater wiring from a safety and compliance perspective.

Common Gauge Recommendations for Wiring a Sauna Heater

So what gauge wire for sauna heater is best for your situation? This chart below should point you in the right direction for wiring a sauna heater:

Sauna Heater Size (kW)	Amps (Approx.)	Recommended Wire Gauge (AWG)	Breaker Size (Amps)
3 kW	12–14 A	12 AWG	15 A
4.5 kW	18–20 A	10 AWG	25 A
6 kW	25 A	10 AWG	30 A
8 kW	33 A	8 AWG	40 A
9 kW	37–40 A	8 AWG	45 A
10.5 kW	44 A	6 AWG	50 A
12 kW	50 A	6 AWG	60 A

Don’t forget to account for the nuances we mentioned above, though. If the sauna heater is more than 50 feet from the power source, size up a gauge or two to reduce voltage drop. 

Regardless of your chosen wire gauge make sure to use copper wire unless otherwise stated by the manufacturer. Always use wire rated for high-temperature environments, especially for running wiring near or inside sauna walls.

How to Wire a Sauna Heater: Step-by-Step Guide to Wiring a Sauna Heater

Once you’ve got an idea of what gauge wire for sauna heater you need it’s time for the fun part - learning how to wire a sauna heater.

Before we get into the step-by-step guide to wiring a sauna heater, though, we want to reiterate that it’s almost always a better idea to hire an electrician than try to take the DIY route. 

It’ll save you time, stress, and guarantee the job is done right the first time around, preventing you from voiding your warranty or more serious risks associated with improper sauna heater wiring. That being said, here’s how to install a sauna heater.

Tools and Materials You’ll Need to Wire a Sauna Heater

• Voltage Tester
• Wire Cutters/Strippers
• Screwdrivers (Flathead and Phillips)
• Electrical Conduit
• Correct Gauge Wire
• Wire Nuts and Connectors
• Circuit Breaker (sized according to heater specs)
• Drill (if mounting conduit or panels)
• Sauna Control Panel (if applicable)

Safety First!

Before starting any electrical work turn off the power at the main breaker. If you have a voltage tester, confirm there’s no current present before proceeding.

We also recommend wearing insulated gloves, safety glasses, and non-conductive footwear to protect yourself from accidental contact with live circuits. 

Take a moment to be realistic with yourself about how confident you feel in learning how to wire a sauna heater. If you have any doubts or lingering fears, stop what you’re doing and call an electrician to take it from there.

Step 1: Verify Power Supply Requirements

Double-check the voltage and amperage requirements in your sauna’s user manual, but it should be 240v here in the US. Most residential installations use single-phase power whereas commercial setups call for three-phase wiring.

The breaker needs to match the heater’s amperage draw, which can range from 15A to 60A. At this point it’s time to get to work installing the circuit breaker.

Step 2: Install the Electrical Conduit and Breaker

Most saunas call for their own breaker on your electrical panel, which should be a double-pole breaker for 240V heaters sized to match your heater’s amperage.

Use a metallic conduit to protect the wiring from physical damage and heat exposure. This is especially important around the sauna. Fasten the conduit to walls, ceilings, or framing using the appropriate clips and anchors.

Step 3: Run the Correct Gauge Wire

They say measure twice, cut once. Take your time to confirm the length of your wire run from the breaker to the heater itself, with extra length for connections and room for error. 

Feed the correct gauge wire through the conduit and make sure there aren’t any kinks or sharp bends. These will just pose a problem later on. Then, label your wires. You might have different labels for:

• Hot (L1 and L2)
• Neutral (if applicable)
• Ground wires

This makes it easier to identify the wires later on if you need to replace them or move the sauna.

Step 4: Connect Wires to the Sauna Heater

Now it’s time to actually start wiring a sauna heater. Open the heater’s wiring compartment to expose its wiring terminals. Begin by attaching the hot wires (L1 and L2) to the right terminals, and tighten the connections with a screwdriver.

Next, you can connect the ground wire to the heater’s grounding terminal for safety in case a fault occurs. Some heaters have a neutral wire, and if yours does, go ahead and connect that one to its designated terminal last.

Step 5: Wiring the Sauna Control Panel (if applicable)

The sauna control panel may have its own wiring configuration. Install it outside the sauna room to prevent heat exposure, always adhering to the guidelines in the manufacturer’s manual.

Run the control wires from the panel to the sauna heater and pay close attention to making the proper connections for temperature sensors and timers. Double-check your work against the wiring diagram in your user control panel manual before proceeding.

Step 6: Final Inspection and Testing

Most of the hard work is done at this point, it’s just a matter of confirming all wires are securely fastened, properly insulated, and free from damage. Use your voltmeter to check for continuity and verify there are no shorts before turning anything on.

At this point, you can restore power at the main panel and turn on your sauna heater to test its functionality. Check for any unusual noises, smells, or error indicators. There you have it, you know how to wire a sauna heater!

Should You Let an Electrician Handle Your Sauna Heater Wiring?

Even with these tips on how to install a sauna heater, it’s worth paying a bit more to leave this job to a licensed electrician. The risks of improper sauna heater wiring are just not worth it:

• Electrical Fires: Incorrectly sized wires, loose connections, or poor grounding lead to overheating, and in turn, an elevated risk of electrical fires.
• Electric Shock Hazards: Mistakes in wiring may expose live circuits, which increases the risk of severe electrical shock. This risk remains even after installation as faulty wiring can pose a threat anytime you use the sauna.
• Tripped Breakers and System Failures: Improper load calculations or incorrect breaker sizing can just create headaches. Frequent power disruptions compromise your sauna's reliability and enjoyment, and could even damage your heater’s components.
• Voiding Manufacturer Warranties: Most sauna heater manufacturers explicitly require professional installation for the warranty to remain valid. DIY mistakes could leave you footing the bill for future repairs. Even if the failure is no fault of your own, not being able to provide proof a professional installed your heater will void your warranty.
• Code Violations and Legal Liabilities: Not meeting local electrical codes leaves you exposed to failed inspections, fines, and legal issues, especially if a wiring fault causes injury or property damage.

Licensed electricians are familiar with local and national electrical codes, so you never have to worry about compliance. More importantly, though, you never have to worry about the safety or longevity of your sauna.

Some homeowners have experience handling straightforward electrical work and might be able to handle this job as well, but be realistic with yourself. If you’re not 100% confident in reading wiring diagrams, using a multimeter, or understanding grounding requirements, don’t bother.

Parting Thoughts on How to Install a Sauna Heater

As we conclude this guide on how to wire a sauna heater we hope you feel clear about what your next steps should be. Although it’s natural to want to save money and get your sauna heater wired now, DIY sauna heater wiring is not right for everyone.

It’s worth waiting a bit longer and paying for a professional electrician to handle every aspect of wiring a sauna heater, from figuring out what gauge wire for sauna heater is optimal to actually completing the project.

But whichever approach you take, remember that Nordica Sauna is your one-stop shop for all things sauna, from the structures themselves to the premier selection of heaters in North America.

All our heaters are sourced from industry-leading brands, too, like Harvia sauna heaters and HUUM sauna heaters. We can help you choose between Harvia vs HUUM if you’re not sure which is right for you.

We carry all types of sauna heaters, including electric sauna heaters, wood burning sauna heaters, and even some natural gas options. Whether you’re trying to heat an indoor vs outdoor sauna, your search ends here.

You’ll enjoy the lowest sauna heater prices thanks to our price-matching and free shipping policies. Plus, you can easily finance the purchase and even use HSA/FSA funds in some cases.

So, what are you waiting for? Upgrade your sauna experience with a reliable, efficient heater from Nordica Sauna today. Our customer service team is on standby ready to offer a personalized recommendation. Shop now or connect with our experts to get it right!