Tale of 5 hygrometers

Here are some of the results from the testing we are doing.

http://www.bargainhumidors.com/image...hygrotest1.jpg

What am I looking for? Consistency. The hygrometers have to be consistent i.e. read the RH value within their stated accuracy range.

In the top left corner we have a group of Western Caliber hygrometers. The stated accuracy on these is 3% which means when you take the plus side and minus side, they shoudl all agree within 6% of each other. They agree within 3% having a range from 45% to 47% which is better than their stated accuracy.

To the right of them is the Little Havana pen style hygrometer. It has an accuracy of 1.5% which means a variance of 3% across them. These range from 46% to 49%. (One was DOA out of the box.)

To the right of those is the Csonka digitals. No clue what their stated accuracy is, because one was never given. They range from 50% to 51% with one being dead.

In the middle is the digital pen everyone raves about. I only had two of these which is unfortunate, because a group of 10 - 20 of them would probably surprise you with as much as everyone raves about them. These have an accuracy of 4%, so the 1% variance between them is very good. We have a batch of 10 of them coming just to give a reference point, but amongst the last 300 we have handled, we have seen as much as a 55% swing across a batch of 50 of them and an average variance of 12% - 14% across a batch which is WELL outside the 8% maximum variance we should see.

On the bottom is the digital hygrometer with hi/lo alarm. It has an accuracy of 4% and these are showing a range from 46% - 51% which is within tolerances.

Do I have one of those so called "control" units or "reference" hygrometers? Nope. Complete waste of time, because their variance of 1.5% - 2% is no better than the variance 4 of the different hygrometers are displaying.

I've rotated each of these through my humidors in groups and the higher RH doesn't introduce any logarithmic drift causing them to become less accurate as you increase the RH.

Oh, the other comparison - pricing:
Western Caliber - $25
Little Havana - $25
Csonka - $40
Digital Pen - $42
Digital with alarm - $25

Which one is reading the correct RH? ALL of them. The RH in my living room is approximately 50% give or take a little. All of them read within the approximate range they should. All of them have reading overlap. You put two of them side by side and you are going to get different readings just like shown.

These have been running for at least 3 days to eliminate any variances in starting them up. There is a ceiling fan directly above them on the low setting to provide constant airflow to prevent RH pooling.

This simply tells you that what you are looking for in a hygrometer is something that is accurate enough. Absolute precision is an impossibility. If someone is telling you they can cull out hygrometers with a 2% or less accuracy using any home-cooked method (i.e. something that doesn't involve a scientific clean room), they are feeding you a line and fooling themselves.

Spend your money in the humidification system to provide you with a unit that can maintain the humidity in your humidor. Get a hygrometer and use it like it was intended to be used, a gauge that will alert you to changes in humidity. How much of a change? About 4% - 5%. A swing of 4% - 5% over a short period of time is going to have no effect on your cigars. If you are trying to control within 2%, good luck, because all it would take is a storm front to roll through, change the barometric pressure, and you just blew through 2% on your gauge.

Get a good humidifier, season your humidor, get it stabilized, spend your time enjoying your cigars instead of obsessing with exact RH. Refill the humidifier when your gauge tells you the humidor has dropped more than you want it to.

In the coming months, I'll also be releasing a paper on hygrometers that takes you through all of the technical details, calibration methods, and other information for any of the techno-geeks out there who are interested. It just takes time to pull the volumes of information together and put in into something that is understandable.