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TFA synthetic hair hygrometer or spring

Updated: October 2026

You have seen synthetic-hair on a TFA page and you want to know which of these five hygrometers the phrase belongs to. Search mostly compares digital with analogue, or it shows a Klimatest and a sauna dial that are not in this set. English pages name the synthetic-hair movement on two models here, and they stay silent on the other three. Silence is not a hidden hair movement. This map is for the [TFA Dostmann hygrometer comparison](/hub/climate-measuring/tfa-dostmann-hygrometer). The purchase order is the [buying guide](/hub/climate-measuring/tfa-dostmann-hygrometer/sub/tfa-dostmann-hygrometer-buying-guide). Products Compared used TFA’s English pages and the amazon.co.uk capture of 15 October 2026. A qualifying purchase can earn us a commission at no extra cost to you.

You have seen synthetic-hair on a TFA page and you want to know which of these five hygrometers the phrase belongs to.

Our top picks

TFA TFA 45.2027 indoor hygrometer

Best overall

TFA TFA 45.2027 indoor hygrometer
8.0/10about £17.39
View offer
TFA TFA 45.2045.02 indoor-outdoor hygrometer

Best value

TFA TFA 45.2045.02 indoor-outdoor hygrometer
7.9/10about £9.71
View offer
TFA TFA 45.2043.51 synthetic-hair hygrometer

Alternative

TFA TFA 45.2043.51 synthetic-hair hygrometer
6.0/10about £17.96
View offer
On this page
  1. 1.Two movements, not a digital-versus-analogue essay
  2. 2.The English pages that say synthetic-hair
  3. 3.The three pages that do not say it
  4. 4.What the phrase does not prove

Two movements, not a digital-versus-analogue essay

TFA’s English pages describe two analogue movements made in-house: a patented synthetic-hair fibre, and a spring with a coated bimetallic coil. The thermo-hygrometer family page says both exist, and that analogue meters need regeneration. Every model in this set is analogue. A patent is a design, not a test score. The split that matters is which English page names the fibre. Regeneration still applies to both movements. A spring dial does not skip it, and neither does a page that never names a movement. The steps are on the how to regenerate a TFA hygrometer page. The cloth is the wrong method for an electronic TFA meter.

The English pages that say synthetic-hair

Two English pages in this set say synthetic-hair. The 45.2027 page, the metal-ring thermo-hygrometer, uses synthetic-hair precision hygrometer. The 45.2043 page uses the same phrase for a room-climate movement with colour-coded comfort levels. The amazon model here is the 45.2043.51. A 45.2042 in the same results is a different number. The capture copies only one of those pages onto amazon.co.uk. The 45.2043.51, B01KLSUYLK, has the phrase in the bullets, with Dry, Ideal, and wet. The 45.2027, B004A5FSXA, does not name a sensor, and its title says German. Both can stand: the English page names the movement, and the UK listing does not. These two are the dearer indoor dials, £17.39 and £17.96. That price is not proof of a tighter tolerance. No ±3 %, ±4 %, or ±5 % RH is printed for these analogue models.
TFA TFA 45.2027 indoor hygrometer

Testsieger

TFA TFA 45.2027 indoor hygrometer
8.0/10about £17.39
View offer

The three pages that do not say it

The English pages for the 45.2024, the 45.2041.42, and the 45.2045.02 do not say synthetic-hair. They also do not say the movement is the coated spring. You may describe TFA’s range as a fibre and a spring, and then say these three pages do not tell you which they use. The 45.2024 and the 45.2041.42 are the small indoor dials. The 45.2045.02 is the indoor-outdoor dial whose country of origin is China. Metal, Germany, China, and a low price are shopping details, not a sensor name. The Klimatest 45.2030, the sauna thermo-hygrometer 40.1006, and a 45.2020 are real products and the wrong SKU. The best-for-the-job page can say which of the five to open. It cannot relabel the three silent pages.

What the phrase does not prove

Synthetic-hair, on the two pages that use it, means TFA has named that movement. It does not publish a humidity accuracy you can hold the other three to. Temperature lines on the cards, ±1 °C or ±2 °C or both on the 45.2043.51, are a listing fact. They are not a hair-versus-spring result, because the three silent models are not identified as spring models. What you may write is narrow. The 45.2027 and the 45.2043.51 are the models whose English pages say synthetic-hair. Only the 45.2043.51 also says it on the amazon.co.uk bullet. The other three stay unlabelled. About £17 to £18 is what you pay to have the sentence on a page you can cite. Naming the fibre does not exempt that pair from regeneration, and silence does not exempt the other three.

Common questions

What are TFA’s two analogue movements?
A patented synthetic-hair fibre, and a spring with a coated bimetallic coil, both described on TFA’s English pages as in-house analogue movements. Analogue meters need regeneration either way. The pair is a range fact. It becomes a model fact only where that model’s English page says which movement it uses. A patent is not a test score.
Which of these five English pages say synthetic-hair?
The English pages for the 45.2027 and the 45.2043.51 say synthetic-hair. The 45.2043.51 also prints it on the amazon.co.uk bullet. The English pages for the 45.2024, the 45.2041.42, and the 45.2045.02 do not. Those three stay unlabelled. A 45.2042 in the same search is not the 45.2043.
Does the amazon.co.uk listing for the 45.2027 say synthetic-hair?
The captured listing does not name a sensor, and the title says German. TFA’s English product page for the 45.2027 does say synthetic-hair precision hygrometer. Cite the English page for the movement and the UK listing for the scale. One sentence does not cancel the other.
Can I call the 45.2024, the 45.2041.42, or the 45.2045.02 a hair hygrometer?
Their English pages do not say synthetic-hair, and they do not say the movement is the coated spring. Other TFA products, including the Klimatest 45.2030 and the sauna dial 40.1006, can use hair wording and still be the wrong model. Describe the range, then say these three pages do not name the movement.
Is synthetic-hair the same claim as more accurate?
It is a movement name, not a humidity tolerance. These analogue listings do not print ±3 %, ±4 %, or ±5 % RH. The higher price of the 45.2027 and the 45.2043.51, about £17 to £18, is what you pay for the words on the page that states them. A ±1 °C or ±2 °C line is not a hair-versus-spring result.
Why do search results show a sauna hygrometer and a Klimatest?
The query is broad. The Klimatest 45.2030, the sauna thermo-hygrometer 40.1006, and a 45.2020 are real products and the wrong SKU. Stay with the 45.2027 and the 45.2043.51 when the phrase has to be on an English page.

Related pages

Hygrometer, damp and mould

TFA Dostmann hygrometer

Best TFA Dostmann hygrometer: which listing to open

Which TFA Dostmann hygrometer to buy on amazon.co.uk

How to regenerate a TFA hygrometer after unpacking

Sources

Manufacturer and public UK sources used for this comparison. Listing prices, stars, and review counts are from amazon.co.uk on 15 October 2026.

  1. TFA — English hygrometer instructions (retrieved 16 October 2026)
  2. TFA — thermo-hygrometers (retrieved 16 October 2026)
  3. TFA — frequently asked questions (retrieved 16 October 2026)
  4. TFA — analogue thermo-hygrometer 45.2027 (retrieved 16 October 2026)
  5. TFA — analogue thermo-hygrometer 45.2043 (retrieved 16 October 2026)
  6. Centre for Sustainable Energy — temperature and humidity at home (retrieved 16 October 2026)
  7. GOV.UK — damp and mould in the home (retrieved 16 October 2026)
  8. Consumer Rights Act 2015, section 9 (retrieved 16 October 2026)