The honest core of this site
How we research and score
Every claim we make about a sauna rests on this page. If we get this wrong, nothing else we publish is worth reading.
We do not run a testing lab. We don't have one, and we're not going to pretend we do. When a number in one of our reviews came from a manufacturer's spec sheet, we say so and treat it as a claim. When we couldn't verify something, we say that too — in those words, on the page.
What we actually do
We research. Specifically, we work from:
- Published manufacturer specifications — treated as claims, not facts. We write "JNH rates it ultra-low EMF", not "it is ultra-low EMF". The difference matters.
- Primary technical standards. Heater sizing comes from published cubic-feet-to-kW guidance; running cost from manufacturer kW ratings and the U.S. average electricity price — both checkable, both linked on the page.
- Live Amazon catalog data.Every product on this site was resolved against Amazon's live catalog for its ASIN, image and price. We do not write up a sauna from memory.
- Aggregated owner reviews — treated as evidence, but weak evidence. A recurring complaint across many buyers is a real signal about build or reliability. It is not a substitute for a specification.
What our scores are, and what they are not
Every product carries five metric scores out of 10 (four for small accessories), and an overall score that is simply their mean. These are judgments from documented research.They are not lab measurements, and we will never present them as such — you won't find a fabricated star rating or an invented review count anywhere on this site.
We publish the rubric because nobody else in this category does. If you can't see what a number is made of, the number is decoration.
Infrared / indoor / barrel cabins
- Capacity
- Honest seating — a '2-person' cabin is two people, not 'up to' two.
- Heat & comfort
- Heater count and spread, warm-up, and whether the heat wraps around you.
- Low-EMF
- The disclosed EMF rating, taken as a manufacturer claim — we prefer brands that publish a number.
- Build & wood / install
- Hemlock vs cedar, tolerances, and the 120V-vs-240V electrical reality.
- Value
- Performance per dollar at the LIVE price — so this one moves.
Portable saunas & blankets
- Heat
- How well it actually warms you, dry infrared vs wet steam.
- Build / EMF
- Materials and, for blankets, the disclosed EMF claim.
- Portability / comfort
- Fold-flat storage, and whether it's bearable to use.
- Ease of use
- Setup, moisture management, and the day-to-day chore of owning it.
- Value
- Performance per dollar at the LIVE price.
Sauna heaters
- Heat output
- kW matched to the room it's meant for — not the biggest number.
- Build
- Harvia-grade vs budget, and which part fails first.
- Controls
- Built-in knob vs external digital, and how usable it is.
- Install
- The 240V circuit, clearances, and whether stones are included.
- Value
- Performance per dollar at the LIVE price.
The signature dataset: running cost
The number no competitor publishes, and the one that most often decides a purchase. We compute cost-to-run for every sauna from power (kW) × session hours × your electricity rate ($/kWh), using the U.S. average residential price and a stated regional range, with the arithmetic shown so anyone can reproduce it. See what a home sauna costs to run.
Why our scores can change without the product changing
The Value metric is computed against the product's live price. So when a cabin drops in a sale, its Value score goes up and its overall score moves with it — even though the cabin is identical. That is deliberate and honest: "is this worth the money?" is a question about the money, and the money changes.
How the prices work
- Prices come from the Amazon Product API, refreshed on a daily schedule.
- Every price is stamped with the date we fetched it. The most recent refresh was Jul 25, 2026.
- If our price data is more than 48 hours old, the number disappears.The button falls back to "Check price on Amazon". We would rather show you nothing than a figure that has rotted.
- If a product has no buyable offer, we say so and show no price — rather than quietly leaving last month's number on the page.
What we will never do
- Write "we tested", "hands-on", or "we measured" — because we didn't.
- Invent a price, a rating, a review count, or a specification.
- Publish a customer endorsement. We have no customers; we sell nothing.
- Let a commission rate change a ranking.
Who writes this
Reviews and guides on Sauna & Slate are written and edited by Stephen V., an enthusiast, not a lab. The site is published by Type 5 Marketing LLC. Every review follows the method on this page.
Tell us we're wrong
If something here is factually incorrect, we want to know, and we'll fix it within 48 hours with a visible correction note — see our editorial policy. Contact us.