Sauna Electrical Requirements: 120V vs 240V Guide

Before you buy a sauna, check what it needs from your electrical panel. Some saunas plug into a normal wall outlet. Others need a dedicated 240-volt circuit wired by an electrician. Knowing which is which up front saves you from a sauna you cannot switch on.

This guide explains the difference, shows what the products in our own catalog list, and covers what to ask your electrician. It is not wiring instructions. All electrical work for a sauna should be done by a licensed electrician, following your local code and the manufacturer's manual.

The short version

  • Most infrared saunas run on 120V. They are typically designed for a standard household circuit, usually 15 or 20 amps.
  • Most traditional electric sauna heaters need 240V. They are usually hardwired to a dedicated circuit with its own breaker.
  • Small exceptions exist on both sides. A few small heaters run on 120V, and a few large infrared cabins need 240V.
  • The product page and the manual decide. Always check the listed voltage and amperage for the exact model.

Why traditional heaters need 240V

Power is voltage multiplied by current. A 15-amp, 120-volt circuit can carry at most 1,800 watts (15 × 120). That is enough for an infrared sauna that draws around 1,500 watts, but nowhere near enough for a traditional heater rated at 4.5 to 9 kilowatts.

Doubling the voltage to 240 volts halves the current needed for the same power. Even so, a full-size heater still draws a lot. The HUUM DROP manual lists these figures at 240V:

HUUM DROP model Output Room volume Amps
DROP 4 4.5 kW 106–247 cu ft (3–7 m³) 18.75 A
DROP 6 6 kW 177–353 cu ft (5–10 m³) 25 A
DROP 7 7.5 kW 247–424 cu ft (7–12 m³) 31.25 A
DROP 9 9 kW 282–530 cu ft (8–15 m³) 37.5 A

The same manual also lists lower outputs for each model when connected at 208V, which is common in apartment buildings and commercial spaces. If your building has 208V service, tell your electrician and check the manual for your heater.

The National Electrical Code treats fixed electric space-heating equipment as a continuous load. In a summary of NEC Article 424, electrical code educator Mike Holt explains that branch-circuit conductors and overcurrent protection must be rated at no less than 125% of the heating load. That is one reason the breaker on a sauna circuit is sized above the heater's running current. Your electrician will work out the right wire and breaker for your heater, your run length and your local code.

What our catalog lists

We went through the voltage listed on every sauna and electric heater in our catalog. Here is what we found.

Electric sauna heaters

Our electric sauna heaters collection lists 7 heaters, rated from 2 kW to 9 kW:

  • 1 heater lists 120V. It is a 2 kW model rated for rooms of 52.9 to 88.2 cubic feet (1.5–2.5 m³).
  • 5 heaters list 220–240V. They are rated at 4.5, 6 or 9 kW, for rooms from 105 to 459 cubic feet (3–13 m³).
  • 1 heater, a 9 kW model, does not state a voltage in its description. Confirm with us before ordering.

So in our range, only the smallest heater runs on 120V. Anything sized for a typical home sauna room needs 240V.

Infrared saunas

Of the 91 infrared saunas in our catalog, 34 state a voltage in their description:

  • 30 list 120V. The amperage they list is usually 15 or 20 amps. One example is a 1-person model that lists 120V/15 amp and 1,450 watts.
  • 4 list 240V. These are larger or combined units, such as hybrid infrared-and-traditional cabins and all-in-one sauna pods.

The other 57 infrared listings do not state a voltage in the description. Check the specifications and images on the product page, or contact us before ordering.

Traditional indoor and outdoor saunas

Among our traditional (non-infrared) indoor and outdoor saunas, 12 state a voltage. Eleven list 220–240V for the heater. One lists both 110V and 220V options. Several also list a second, separate circuit for the lights, audio and control panel. For example, the listings for some Golden Designs traditional saunas specify 240V/40 amp for the stove and a separate 120V/15 amp circuit for the control panel and lighting. Plan for both circuits if your sauna lists them.

Plug-in vs hardwired

A plug-in sauna has a cord and plug and connects to a wall receptacle. Most 120V infrared saunas work this way. Even so, 20 of the infrared listings in our catalog mention a dedicated circuit, meaning nothing else runs on that breaker. Check whether your listing asks for 15 or 20 amps, and whether it asks for a dedicated circuit.

A hardwired sauna heater has no plug. An electrician connects it directly to a dedicated circuit from your panel, often through a disconnect switch. Most 240V heaters are installed this way. The HUUM DROP manual states that only a certified electrician is allowed to connect the heater to the power supply. A KIP heater manual from Almost Heaven Saunas (heater made by Harvia) states that all wiring should be done by a licensed electrician.

Questions to ask your electrician

  • Does my panel have spare capacity and space for a new 240V circuit?
  • Is my service 240V or 208V? (This changes heater output.)
  • What wire, breaker and disconnect does this heater need, based on its manual and the length of the run?
  • Does my local code or the manual call for GFCI protection on this circuit? (Manufacturers differ here. Follow the manual and your inspector.)
  • For an outdoor sauna: how will power reach the sauna, and does it need a subpanel?
  • Do I need a permit and an inspection in my area?

Bring the product's manual or specification sheet to the conversation. Manufacturers list the exact electrical requirements for each model, and your electrician should follow them.

Match the heater to the room first

Heater size drives the electrical requirement, so size the heater before you plan the circuit. The HUUM DROP manual notes that walls of uninsulated brick, tile, glass or log add to the effective volume, and that uninsulated saunas such as barrel or outdoor saunas need about 1.5 times the calculated volume. Our sauna heater size calculator works out your room volume and the heater output range that fits. Then compare heaters on our electric sauna heaters page by their listed room volume and voltage.

Bottom line

If you want a sauna that plugs into the wall, look at 120V infrared saunas and check the amperage they list. If you want a traditional Finnish-style sauna with hot stones and löyly, plan on a 240V hardwired heater and a licensed electrician. Either way, read the product's electrical specifications before you buy, and contact us if a listing is unclear.

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