How we research

Specifications come from the maker

Seating capacity, dimensions, wood, heater output, the room size a heater is rated for, electrical supply and stone capacity are taken only from the maker's own website, specification sheet or manual. Each row in a specification table links to the source it came from, and the note under the table gives the date we read the maker's specifications.

Retailer listings are not used as sources for specifications. Retailers often copy, round or mix up figures between models, so a figure found only on a retailer page is left out.

We print a maker's figure in the maker's own units and wording. When two pages on a maker's site disagree, or we cannot find a figure again on the maker's own page when we check it, we leave it out.

Comparisons use the same figures

Comparison pages set two or three products side by side using exactly the figures on their product pages. We pair products that the makers' own figures put in the same class: the same kind of sauna for a similar number of people, or heaters rated for overlapping room sizes. A dash in a cell means the figure is not on the maker pages we cite.

Guides cite makers and recognised bodies

Guides draw on makers' installation manuals and published guidance, standards and code publishers, and sauna societies. Each paragraph that states a fact links to its source.

Owner reports

Where a page summarises what owners report, the summary says how many reports it rests on and from how many places. We publish one only when at least 10 independent reports from at least 2 separate places agree, and we label it as a summary of reports. It is never presented as our own test.

What we never publish

• Health claims of any kind.
• Estimated or "typical" figures in place of a maker's published one.
• Our own electrical, structural or fire-safety instructions.
• A retailer's price. The only price we show is the price the maker's own site showed in US dollars, with the date we read it, so you can filter by budget. Prices change; the seller's page is the one to trust at checkout.
• A quality score. The finder's quality filters are what makers state (a warranty, a safety listing such as ETL or UL), never our rating.

Corrections

If a figure is wrong, or a maker has changed a model, write to us from the contact page. We check the maker's current page and correct the entry.