Methodology
How the Spec Score works
A simple, public formula over specs the brands publish. It helps you compare quickly; it is not a test result, a review of build quality, or a health claim.
Plain truth: we have not tested these saunas or cold plunges hands-on. The Spec Score only turns published numbers into a 0–10 scale so models are easier to compare. If a brand doesn’t publish a spec, we give that criterion a neutral 5/10 and say so on the card. Commissions never change a score: the formula is the same for every brand, and it is written out below so you can check our math.
Saunas: four criteria, equal weight
| Criterion | What we use | How it maps to 0–10 |
|---|---|---|
| Heat | Maximum temperature the brand publishes | Infrared scale: 140°F = 5, rising evenly to 175°F = 10. Traditional (stone heater) scale: 176°F = 5, rising evenly to 210°F+ = 10. The two types are scored on separate scales because they heat differently. |
| Install | Published electrical requirement | Dedicated 120V circuit = 10. Needs a 240V circuit (usually electrician work) = 7. Not published = 5. |
| Warranty | Main warranty term (cabin/heaters) | 1 yr = 5, 2 yr = 6, 3 yr = 7, 5 yr = 8.5, 7 yr = 9.5, 10 yr or lifetime = 10 (straight lines in between). Not published = 5. |
| Value | Price ÷ listed seats, using the price we saw on the brand’s site | $2,000 per seat or less = 10, falling evenly to $5,500+ per seat = 5. Seat count not published = 5. |
Cold plunges: four criteria, equal weight
| Criterion | What we use | How it maps to 0–10 |
|---|---|---|
| Cold | Lowest published water temperature | 45°F = 6, 37°F = 8.5, 32°F or colder = 10. |
| Install | Published electrical requirement | Standard 120V circuit = 10; 240V = 7; not published = 5. |
| Warranty | Main warranty term | Same scale as saunas. |
| Value | Price ÷ gallons | $50 per gallon or less = 10, falling evenly to $100+ per gallon = 5. |
The overall score
The Spec Score is the plain average of the four criteria, rounded to one decimal. Every product card shows all four sub-scores and the spec each one came from, so you can see exactly why a model scored the way it did.
What the score doesn’t capture
- Build quality, fit and finish, comfort, noise, or how evenly a cabin heats. Those need hands-on testing, which we haven’t done.
- Customer service, delivery experience, or long-term reliability.
- Whether a sauna suits your health. We don’t make health claims; ask your doctor.
- Sales that started or ended after the date shown. Prices change often; always confirm on the brand’s site.
Because of that, a higher score is a starting point, not a verdict. Our written picks (“Best for…”) weigh things the formula can’t, like footprint, steam, or a split warranty, and we explain each one in the article.
Corrections
If a brand updates a spec or we got something wrong, tell us at tagzlabs.abq@gmail.com and we’ll fix it and note the date.