Important: Check the accuracy of your hygrometer

[muzz76]

I've never really trusted these things for their accuracy but like probably alot of us, developed somewhat of a false comfort that what it read was either right or within a safe margin.

I found a trick online that cigar and humidor dealers and afficianados use to tell accuracy. Take a small container or lid that is just large enough to contain a teaspoon or two of salt, fill it with salt and add just enough water to moisten and saturate it, not disolve it. Take the container and your hygrometer and place in a sealed container or ziplock bag, wait 8hrs and the reading should be exactly 75% humidity. I'm not sure of the exact science behind this but I read it on a couple different reputable sites and it seems to be a common practice.

To the verdict of my own trusty rad shack hygrometer, actually I tried the process twice on three different of the same model, the one with temp/humid and min/max features.

hygrometer 1: read 65%
hygrometer 2: read 66%
hygrometer 3: read 62%

The variations ranged from 8-12% too low. I put some trust in these gadgets and to me this is downright scary. Many analog models have a screw which enables you to re-calibrate it yourself but I don't believe these digital ones have that feature. I could always note the degree to which each is off and monitor the humidity accordingly but I paid good money for these and I believe my instruments have been put in jeopardy because of them...i'm returning them to rad shack asap and will keep exchanging until I find some accuracy and consistency. My instruments have so far suffered no ill effects and I don't mean to put a scare into anyone but I thought people should be aware.

Derek

Confucius say, man with watch always knows what time it is. Man with two watches is never sure.

I've always taken the readings of these inexpensive devices with a grain of salt (hehehe...) It's good to learn a calibration method. I have two analog ones in the house and the Radio Snack in the case myself.

Bob