How we rate
The Contrast Index compares saunas and cold plunges on published specs. Here's where those specs come from and what we do when they're missing or don't agree.
Where the specs come from
Every spec for the 40 models in the index comes from the manufacturer's own website, spec sheet or manual. Each model page links to its source and shows the date we checked it. We don't copy specs from retailers or other review sites.
When a spec is missing
If a brand doesn't publish a spec, we mark it "Not published." We never estimate, average or fill gaps from other sources. A missing spec is useful to know: if a brand won't say how much water its chiller can cool, ask before you buy.
When a brand's own pages disagree
Sometimes a brand lists two different prices, weights or warranties on its own site. We record what each page says in the model's "Notes on the source" section and don't pick one.
Prices
Prices are what the brand listed on the date we checked. Sauna and cold plunge brands run frequent sales, so the price you see at checkout may differ. We recheck prices monthly.
Scores
Right now the index compares specs; it doesn't give products scores. When we add ratings, this page will explain exactly how they're calculated, before any score goes live.
Affiliate links
Some links to brands may be affiliate links, which means we may earn a commission if you buy, at no extra cost to you. Commission rates never affect which products we include, the order they appear in, or what we say about them. Products from brands with no affiliate program are listed the same way as everyone else.
Corrections
If a spec is wrong or out of date, email [email protected] with a link to the manufacturer's page. We'll check it and update the date.