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Steam room thermometer: the Finnish dial is the wrong climate

Updated: October 2026

You have a steam cabin, or a zip-up box in the spare room, and the amazon.co.uk listing says the gauge suits a steam room. The face still runs towards 120 °C, the arc sold for a Finnish stove. A steam room thermometer has to mean something in cooler, saturated air, which is a different job from matching an 80–100 °C set point. This page sets those two climates against the bullets in our [sauna thermometer comparison](/hub/steam-baths/sauna-thermometer). There is no lab test in wet air. Figures were checked on 20 October 2026. A qualifying amazon.co.uk purchase can earn us a commission at no extra cost to you.

You have a steam cabin, or a zip-up box in the spare room, and the amazon.co.uk listing says the gauge suits a steam room. The face still runs towards 120 °C, the arc sold for a Finnish stove.

Our top picks

Funnytek Funnytek portable dial

Best overall

Funnytek Funnytek portable dial
5.0/10about £11.99
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Ulsam Ulsam Round-01

Best value

Ulsam Ulsam Round-01
7.8/10about £12.89
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TFA TFA 40.1055.50

Rank 3

TFA TFA 40.1055.50
8.2/10about £14.39
View offer
On this page
  1. 1.Two rooms, two climates
  2. 2.What steam room means on these listings
  3. 3.What a home owner does not inherit from a licence
  4. 4.Questions about wet air

Two rooms, two climates

A Finnish sauna and a steam room part company as soon as you measure the air. SPATA, the UK spa trade body, puts a conventional sauna usually above 80 °C, with humidity often about 5–20%, and a steam room typically up to 45 °C at about 90–100% humidity. TFA’s English table puts a steam bath at 40–50 °C and 100% relative humidity, a sauna at 70–100 °C and 5–10%, and a biosauna at 45–60 °C and 40–55%. Keep 45 °C with SPATA and 40–50 °C with TFA. A scale drawn for 80–120 °C spends most of its arc above a steam cabin, so at 45 °C you are on the coarse lower marks. The spring has not failed, and hanging the face lower will not redraw the scale. Where a Finnish cabin gauge should hang is a separate job, in the guide to mounting a sauna thermometer.

What steam room means on these listings

On these amazon.co.uk pages, steam room is a bullet, not a steam-bath rating. Hacaroa runs from 70 to 250 °F, about 21–121 °C, Funnytek pairs a lanyard with 70–210 °F, about 21–99 °C, and YIWONFU names a humid steam room and a Finnish sauna in one line. Hojalis, PCXWTLN and Haosie use similar wording, with no 40–50 °C specification. A face near 120 °C can still be a fair Finnish instrument. It does not become a steam room thermometer because the bullet borrowed the phrase. UK reviews of a TFA gauge mention a bio sauna, humidity that stopped after heavy moisture, and melted plastic on the back. A melted case is a return, not a calibration trick.
Funnytek Funnytek portable dial

Testsieger

Funnytek Funnytek portable dial
5.0/10about £11.99
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What a home owner does not inherit from a licence

Redbridge Council’s code covers licensed special-treatment premises, not a cabin at home. It describes steam rooms up to 50 °C at 80–100% relative humidity, and treats an in-room thermometer as the preferred check. Royal Greenwich’s licence terms say a steam room must not exceed 50 °C. Those lines bind the licence holder. They do not require a private household to fit a steam room thermometer. A home cabin near 50 °C is at the top of that band, a little above SPATA’s typically up to 45 °C. The gauge can tell you whether the generator is there. It does not clear a longer session or replace medical advice. If the dial fogs, sticks, or softens, section 9 of the Consumer Rights Act 2015 is the quality route when a sauna-labelled gauge melts or never moves. Nothing in this set was tested here in saturated air, so this page names no steam-bath winner.

Questions about wet air

Near 100% relative humidity the glass can mist even when the mechanism is sound. Wipe the outside once the pane is cool enough to handle. Mist sealed inside the case will not wipe off. A stuck humidity needle is a different fault from a stuck temperature needle. TFA’s hair-hygrometer step is a damp cloth for about 20 minutes, then a reading around 90–99%. That can revive a hair element, and it will not straighten a warped case. If it still fails, return the gauge. A portable steam box is not a tiled steam room, though the air can still be warm and wet. Funnytek’s lanyard is the only portable-box line in this set, on a 70–210 °F dial, so you can see the needle without a scale drawn for 40–50 °C. A remote probe is a different product, set out on the analogue versus digital sauna thermometer page, and the sauna thermometer buying guide covers how to choose a face.

Common questions

What temperature is a steam room compared with a Finnish sauna?
SPATA puts a steam room typically up to 45 °C at about 90–100% humidity, and a conventional sauna usually above 80 °C. TFA’s table puts a steam bath at 40–50 °C and 100% relative humidity. The two ceilings are not one figure.
Can I use a sauna thermometer in a steam room?
You can hang a Finnish dial in a steam room, and it may move, but the scale is aimed at about 80–120 °C. Steam air sits around 40–50 °C, so the needle uses only the coarse bottom of that face. A housing that softens, or a needle that never leaves the stop, is a fault in the goods.
What humidity should a steam room show?
SPATA puts a steam room at about 90–100% humidity, and TFA’s table lists a steam bath at 100% relative humidity, against 5–10% in a Finnish sauna. Redbridge’s 80–100% figure is for licensed premises, not a private home.
Is a portable steam box the same as a steam room?
A portable box is a smaller, usually fabric enclosure, not a tiled cabin. The air can still be warm and wet. Funnytek is the only listing in this set with a lanyard, and its dial is still 70–210 °F, about 21–99 °C.
Does a home have to fit a thermometer by law?
Redbridge’s preference for an in-room thermometer, and Greenwich’s rule that a steam room must not exceed 50 °C, apply to licensed premises. They do not create a duty for a private UK home. If a sauna-labelled gauge melts or never moves, the Consumer Rights Act 2015, section 9, is the quality route with the seller.

Related pages

Best sauna thermometer

Sauna thermometer

Analogue vs digital sauna thermometer: heat limits

Sauna thermometer buying guide: scale, unit and power

Where to hang a sauna thermometer opposite the stove

Sources

Sources taken from the research digest. Listings were checked on 19 October 2026.

  1. Oceanic Saunas — combined thermometer and hygrometer (retrieved 19.10.2026)
  2. Auroom — thermo-hygrometer sheet (retrieved 19.10.2026)
  3. TFA Dostmann — analogue sauna thermo-hygrometer 40.1055 (retrieved 19.10.2026)
  4. TFA — English instruction column, climate bands (retrieved 19.10.2026)
  5. Wild Sauna UK — analogue versus digital (retrieved 19.10.2026)
  6. legislation.gov.uk — Consumer Rights Act 2015, section 9 (retrieved 19.10.2026)
  7. GOV.UK — product safety advice for businesses (retrieved 19.10.2026)
  8. Redbridge Council — saunas and steam rooms code of practice 3 (retrieved 19.10.2026)