How to read sauna specs: heater kW, wood, capacity, voltage and EMF claims

Last updated Oct 17, 2026. Figures come from our nightly price checks, as of the date shown in each section.

Sauna listings throw a lot of terms at you: kW, 240V, Canadian hemlock, thermo-aspen, full-spectrum, low EMF. This guide explains what each spec means for a buyer, how often stores actually state it, and what it tends to sell for. Figures come from the 825 sauna models we tracked across 20 stores on October 17, 2026.

We don’t cover health effects, and we don’t evaluate brands’ health or wellness claims.

How often stores state each spec

Out of 825 sauna models, the store stated:

So even basic specs are missing from many listings. If a spec matters to you and the listing doesn’t state it, ask the store in writing before you buy.

Heater power (kW)

For traditional saunas, heater power is given in kilowatts. A bigger room, or one with lots of glass, generally needs a more powerful heater. Heater makers publish sizing charts by room volume. That’s the right way to choose, not “bigger is better.”

Among models stating heater power:

• 8 kW is the most common rating (118 models; median lowest price $8,070).
• 6 kW comes next (86 models; median $7,599).
• 9 kW (31 models; median $16,360) and 10.5 kW (9 models) appear mostly on larger or premium saunas.
• 4.5 kW (25 models) appears on smaller saunas.

For infrared saunas, power is usually shown in watts for the whole unit (for example 1,700 to 1,900 W on some models), or per panel. That isn’t directly comparable to a traditional heater’s kW rating.

Voltage and amps

• 120V: plugs into a standard outlet, often needing a dedicated circuit. 112 models state 120V, mostly smaller infrared saunas (median $3,549).
• 240V: needs a dedicated circuit wired by an electrician. 81 models state 240V (median $8,500).
• “120V or 240V”: 85 models depend on the option chosen, usually the heater.

Always check the amps (for example 15A or 20A at 120V, or the breaker size for 240V) and whether a dedicated circuit is required. This decides your electrical cost (see what a home sauna really costs).

Wood

Wood affects look, smell, durability outdoors, and price. Here’s how the most common stated woods compare on median lowest price:

Read this table with care. Wood is tied up with everything else: hemlock is common on small indoor infrared cabins, while aspen and spruce show up on large premium traditional saunas. The table shows what saunas made of each wood sell for, not what the wood itself costs.

Terms you’ll see:

• Cedar (red or white): widely used for outdoor barrels and cabins. Has a distinct smell.
• Hemlock / Canadian hemlock: pale, light-scented, common on indoor infrared cabins.
• Spruce / Nordic spruce: traditional in Nordic saunas.
• Aspen: pale, smooth, often used for interiors and benches.
• Thermo- (thermally modified) woods: wood heat-treated to change its color and how it reacts to moisture. Common on modern cubes and cabins.

Capacity

Capacity is the store’s claim of how many people fit. It’s not standardized. Compare bench length and interior dimensions when they’re listed. In our data, stated capacities range from 1 to 8+ people, with 2-person (102 models), 6-person (85) and 3-person (83) the most common.

Heat type

Infrared, full-spectrum infrared, traditional and hybrid saunas differ in price, placement and wiring. We compare them in detail in infrared vs. traditional home saunas.

Max temperature

Only 155 models state a maximum temperature. Infrared models that state one almost all say 140°F, and traditional models mostly say 190°F or more. That reflects how the heater types are specified. It isn’t a quality ranking.

EMF claims, explained neutrally

“EMF” means electromagnetic fields, which electrical devices produce. Many infrared sauna listings advertise “low EMF” or “ultra-low EMF” heaters.

How common is it? In the product descriptions of the sauna listings we track, 330 of 1,002 mention EMF, at 14 of our 20 stores. For infrared listings it’s 322 of 380. A few stores even offer an “EMF rating” as a selectable option (16 listings).

What we can and can’t tell you:

• We don’t measure EMF, and we don’t take a position on health questions about it. That’s outside what we cover.
• There’s no single standard for “low EMF” in sauna marketing. Readings depend on what’s measured (magnetic or electric fields), the meter, the distance from the heater, and where in the sauna the reading is taken.
• If it matters to you, ask the store for the test method, distance, the measured values, and who did the testing. Compare saunas only on figures measured the same way.

We list EMF wording only as part of the product description, never as a feature we’ve verified.

Warranty

215 models state a warranty. Warranty terms often differ by component (cabinet, heater, electronics) and can come with conditions (licensed electrician, outdoor cover). Compare those conditions, not just the number of years.

Other features you’ll see

Wi-Fi or app control (stated on 184 models), Bluetooth audio (232), and color or chromotherapy lighting (223, which we record only as a lighting feature). These are convenience features. Price them as options if they’re optional.

Spec checklist before you buy

1. Heat type and heater: included? kW or watts? controller?
2. Electrical: voltage, amps, dedicated circuit?
3. Wood: interior and exterior, and is it thermally modified?
4. Size: exterior footprint, interior bench length, ceiling height.
5. Placement: indoor, outdoor, or both, and what the warranty requires.
6. Warranty: by component, with conditions.
7. Delivery: curbside or inside, and assembly options.

Use the compare page to see stated specs side by side, and all saunas to filter by heat type, style, location and capacity.

Where these numbers come from

Nightly check of 20 sauna stores on October 17, 2026: 825 models from 1,002 listings. Specs come from each store’s own listing and are left blank when the store doesn’t state them. EMF counts are text matches for “EMF” in the stores’ public product descriptions.