Sauna electrical requirements: 120V or 240V, and what to tell your electrician
The single most common surprise for new sauna owners is the wiring. Here's what each type of sauna needs, roughly what it costs to install, and the exact questions to ask so you get one quote instead of three.
By sauna type
| Sauna | Voltage | Circuit | Who installs |
|---|---|---|---|
| Sauna blanket, portable pod, steam tent | 120V | 15A standard outlet | None |
| 1-2 person infrared cabin | 120V | 15-20A dedicated circuit recommended | Usually none, sometimes a new 20A circuit |
| 3+ person infrared cabin, most full-spectrum | 240V | 20-30A dedicated | Electrician |
| Traditional, 4.5-6 kW heater | 240V | 30A dedicated | Electrician |
| Traditional, 8 kW heater | 240V | 40A dedicated | Electrician |
| Traditional, 9-10.5 kW heater | 240V | 50-60A dedicated | Electrician; check panel capacity |
| Wood-fired | None for heat | 120V for lights, if any | None |
120V: plug it in
Most 1-2 person infrared cabins draw 1.3-1.8 kW and come with a standard three-prong plug. They'll run on an ordinary outlet, but brands recommend a dedicated 15A or 20A circuit so you don't trip a breaker when the fridge kicks on. If the room already has a dedicated circuit (many garages and basements do), you need nothing else. Avoid extension cords and power strips; the sustained draw overheats cheap ones.
240V: call an electrician
Larger infrared cabins and nearly all electric traditional heaters need a dedicated 240V circuit, the same kind that feeds an electric dryer or range. The heater is usually hardwired through a contactor or control box rather than plugged in. Typical cost in the US is $300-$800 for a run from a nearby panel, and $800-$1,500+ if the sauna is far from the panel, outdoors, or needs a trench. If your panel is full or undersized (common in older homes with 100A service), a subpanel or service upgrade can add $1,000-$3,000; find this out before you order the sauna.
What to tell the electrician
Give them the heater's spec sheet and these numbers, and you'll get an accurate quote:
- Heater wattage (e.g. 8 kW) and voltage (240V single-phase).
- Required breaker size from the manual (e.g. 40A). Heaters run continuously, so code sizes the circuit at 125% of the load: 8,000 W ÷ 240 V = 33A, × 1.25 = 42A, so a 40A or 50A breaker depending on the manual.
- Wire gauge the manual specifies (typically 10 AWG for 30A, 8 AWG for 40A, 6 AWG for 50-60A copper).
- Whether a disconnect switch is required near the sauna (often yes for outdoor installs).
- GFCI: required for outdoor circuits and in many jurisdictions for any sauna; some heaters are sensitive to nuisance tripping, so ask the brand which GFCI they recommend.
- Distance from the panel to the sauna, and whether the run is indoors, through a wall, or buried outside.
- Lighting and controls: some saunas need a separate 120V circuit for lights, Wi-Fi controls or an infrared add-on.
Permits
A new 240V circuit needs an electrical permit almost everywhere in the US. A licensed electrician pulls it as part of the job (typically $50-$200). Skipping it can void your insurance if anything goes wrong. Outdoor structures above a certain size may also need a building permit; check with your city.
Common mistakes
- Ordering the sauna first and discovering the panel is full.
- Running a 240V infrared sauna on a shared circuit and tripping breakers.
- Using the wrong GFCI type and getting constant trips.
- Putting the heater's control box in the hot room when the manual says outside.
- Forgetting that outdoor runs need weatherproof conduit and boxes.
Need to decide between types first? See infrared vs traditional. Want to know what it'll cost to run once it's wired? See how much a sauna costs to run.