I do not know what this one of the writers expected the criticized as useless at two purchased equipment 10% deviation in the display. Calibrated high-end measuring devices cost many times over. I have 4 devices in use, two of these and two TFA with electronic display (TFA Dostmann digital thermo-hygrometer 30.5015). Do not confuse, they are sufficiently accurate. Both digital agree very well (+/- 2-3% RH), the analog quite well (+/- 3-4% RH). But only above c: a 35% relative humidity. The temperatures are (for this price range) very accurately (+/- 0.5 ° C). Below 35% relative humidity room there are these differences, ie the digital show, for example, 25% RH, an analog 20% rh, the other 32% rh. But so what? The indoor air is too dry, that is the important and correct message. Whether 21% RH or 33% RH interested certainly the civil or meteorologists, but buy other instruments. I specifically bought this analog gauges for my tenant who can recognize as quite simple over the color code when it's time to ventilate is (> 65% RH). And you also get to dry with fairly simple, all under 35-30% RH is too dry. Nice to see over the Farbocdes, better and easier than with digital devices. So all is well, yet a star deduction, because these devices are sold as precision hygrometer what they are I do not think so. Neither above 35% RH still below ...
