How to Choose a Traditional Sauna

Saunas are sold by person count: two-person, four-person, six-person. It is the first thing in the product name, and there is no standard behind it. A "four-person" rating usually means four adults sitting upright, shoulder to shoulder, on one bench. It does not mean four people lying down, or four people comfortable for fifteen minutes.

The numbers that tell you how much sauna you are buying are interior volume and bench size. Here is how far apart three small outdoor cabins from one maker we carry can be:

Shapes that look alike from the yard, and up to 39 percent more air in one than another. Interior volume is also the number the heater has to be sized against, so it is the one you need anyway.

The same logic works in reverse on the heater. One manufacturer we carry puts the same 8 kW stove in a three-person cabin and a six-person cabin. Same heater, half the room: the smaller one comes up to temperature noticeably faster. Neither is wrong. But "six-person, 8 kW" and "three-person, 8 kW" are not the same experience.

Sizing — Heaters are sold with a rated room volume, a minimum and a maximum. Stay inside it. As a rule of thumb, one major heater maker works on about 1 kW per cubic meter of room, roughly 35 cubic feet. Glass and other uninsulated surfaces raise that: that maker counts each square meter of glass, about 11 square feet, as if it added 1.2 cubic meters of room. A sauna with a full glass front needs more heater than its volume alone suggests.

Electric or Wood-Burning — Electric heaters heat on demand, run from a controller and can be scheduled from an app on many models. Wood-burning stoves need no electricity but need a chimney, clearances around the firebox and room to load wood safely. One small cabin we carry is sold electric-only for exactly that reason: its maker judged it too small to give a wood stove safe clearance. Wood-burning also raises questions for your local building rules and your home insurer. Ask both before you buy.

Stones — Water on hot stones is what makes steam, and the stones are part of the heater, not decoration. Check the heater includes them, and how many pounds.

What Is Actually in the Box — This is the trap in this category. Heaters are often sold as configurations: heater, stones, safety guard and controller as separate lines, each with a "none" option. A heater priced without stones, a guard or a controller is not a working heater. On one heater line we carry, the controller alone is a required choice that changes the price substantially. Ask for the price of a complete, installable heater.

Hybrids — A hybrid pairs a traditional stove with infrared panels in one cabin. On the hybrids we carry, the stove runs 170 to 185°F and the infrared mode runs 118 to 132°F. Two different sessions in one room, but the cabin still needs the full traditional electrical supply.

The Circuit — Almost every electric traditional heater needs a dedicated 240V circuit, installed by a licensed electrician. The amperage rises with the heater. Across the saunas we carry:

Two things in that table catch buyers. First, the same 8 kW output is specified at 40 amps by one maker and 50 by another, so never assume: use the figure in that heater's installation manual. Second, many cabins also want a second 120V, 15-amp circuit for lights and audio. Get an electrician's quote for both before you order, and check your panel has the capacity.

Indoor or Outdoor — Saunas are rated for indoor use, outdoor use, or both. An indoor-rated cabin can sometimes sit in a covered space outside, but not in open weather. An outdoor cabin needs a roof built for it and a level, well-drained base, such as a concrete pad, pavers or a deck rated for the load.

Ventilation — A traditional sauna needs fresh air in and air out, set by the maker. Check the vents are part of the cabin, and whether an indoor installation needs anything from the room around it.

Wood Species — Cedar and hemlock are the common choices. Cedar is naturally rot-resistant and has the scent most people associate with a sauna. Hemlock is milder and lighter in color. Some makers heat-treat hemlock for outdoor durability. One maker we carry uses Eastern White Cedar and argues it stays cooler to the touch than Western Red. Ask each seller which species, inside and out, because many cabins use one for the interior and another for the exterior.

Solid Wood or Laminate — Solid wall staves or boards hold up to years of heat and humidity. Laminate or veneer over a frame costs less to make. Ask which you are getting.

Hardware — A sauna lives at high heat and humidity by design. Stainless hardware and aluminum barrel bands resist corrosion. Ordinary steel can rust and stain the wood.

Roof — Outdoor roofs vary: metal, asphalt shingles, or a rubber membrane. Ask what it is and how long it is expected to last before it needs attention.

Door Glass — Clear glass makes a small room feel larger. Bronze or frosted privacy glass matters on an outdoor cabin that faces the neighbors. Either adds to the heater load in section two.

Delivery — Saunas ship by freight, often curbside. One maker's outdoor cabins that we carry arrive in 3 to 10 boxes weighing 695 to 1,575 pounds, with a lift gate to the curb. Getting every box from the curb to the site is your job unless you arrange otherwise, so plan the route and the people.

Assembly — Some cabins arrive as pre-assembled panels that two people can put up in two or three hours. Others arrive as a kit that takes two people most of a weekend. Neither is better, but plan the time and the help, and ask whether professional assembly is available near you.

The Warranty's Fine Print — Read three things:

1. 01Cabin and Heater Separately — The cabin maker and the heater maker are often different companies, with different warranties. Ask for both in writing.
2. 02Residential Only — Many sauna warranties are residential. Commercial use can void them.
3. 03Electrical Work — Some heater warranties require installation by a licensed electrician. Keep the paperwork.

Most sauna kits, and the warranties behind them, are built for the home. A sauna in a gym, spa, studio or rental runs far more hours, often all day, and is used by people who will never read a manual.

The first question for a commercial buyer is whether the heater is rated for commercial duty, and whether the cabin and heater warranties cover commercial use. Get both in writing.

After that:

• Local Codes — A sauna open to the public can face building and health code requirements that a home sauna does not. Check with your local authority before you order, not after installation.
• Heater Listing — Ask whether the heater is safety-listed for the US market by a recognized testing lab, and to which standard. An inspector may ask.
• Heater Capacity — A commercial sauna opens and closes its door constantly. Ask whether the heater recovers heat fast enough for back-to-back use, not just whether it reaches temperature.
• Controls — Timers, scheduling and remote control matter more when staff run the room. Ask what the controller can lock or limit.
• Surfaces and Cleaning — Benches take heavy daily use. Ask what finish they have, what cleaning the wood tolerates, and whether bench boards can be replaced individually.