Five categories
| Heat 25 % | Max temperature against the heat the sauna is made for (90 °C / 194 °F for traditional, 65 °C / 149 °F for infrared), and heat-up time. |
|---|---|
| Materials and health 25 % | The wood (or fabric) around you, what is on the inside surfaces, and for infrared the EMF at the seat: a figure measured by an outside lab beats a maker’s claim, which beats “low EMF” without a number. |
| Build and warranty 20 % | Warranty length (lifetime counts most), a safety listing such as UL, ETL or CE, and a rigid cabin over a tent. |
| Comfort and setup 15 % | Seats, and how easy it is to set up: a standard outlet beats a dedicated circuit, which beats hardwiring; a heater sold separately costs points. |
| Value for money 15 % | The quality points of the four other categories per dollar, on a log scale, compared with the other saunas of the catalog. A sauna sold on dealer quote gets a neutral 50. |
Where the figures come from
The makers’ product pages and spec sheets first, then retailers and independent reviews when the maker publishes nothing. Each sauna page lists its sources. A missing figure is shown as “not published” and scores as unknown: we never fill a gap with a guess.
Reading a max temperature
Makers don’t all mean the same thing. We say which one each figure is: the maker’s published maximum, the highest setting of the control (often not reached in use), the 194 °F (90 °C) cap of US electric heaters certified to UL 875, or the usual range.
What the score doesn’t say
It doesn’t measure anything itself: no lab, no thermometer. It can’t judge build quality you only see after five winters, or customer service. Customer reviews are shown, not scored: too few saunas have comparable ones. Ratings come from the makers’ and retailers’ sites, as they publish them: we don’t check or select those reviews.