Recommendations for the Most Accurate Hygrometer

[epaul]

There are a couple ways to plow this field.

If you want to know how accurate a particular hygrometer is, from a guitar perspective, use potassium carbonate, not table salt (sodium chloride).

Potassium Carbonate will create a relative humidity of 43% in your bag, which is a much more useful metric than that the 75% RH produced by table salt. That 75% RH test is for cigar smokers, not guitar players. Knowing how accurate a digital hygrometer is at 75% RH does not tell you how accurate it is at the range your are most interested in (and if you can calibrate your hygrometer, why calibrate it to be accurate at an RH you aren't interested in?)

I have tested scads of digital hygrometers, and I have had units that were plenty accurate at 43% RH but started to veer off course at 75% .

So, if you are going to test, test well.


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[epaul]

But,


after all my testing, and irrespective of all the different salts I have stashed in my cupboard, this is my very best advice: Just buy a bunch of cheap digital hygrometers and use them to keep each other honest.



If you want to know how accurate they are, put them all on your kitchen table, and if one reads way off of the others, toss it and replace it. If you have five digitals on your table, they won't all read exactly the same, but they should be within three points of their neighbor.

It is handy to have a bunch of little hygrometers on hand. You can keep one in your guitar room/closet. You can keep one in your guitar case. You can even keep a couple in your guitar case and see how effective your humidity device is at distributing humidity to the far reaches of your cased guitar.

Know that humidity readings will vary spot to spot. A window spot will read different than a center of the room spot. A spot by a heater vent swill read differently than a spot next to an oft opened door. And a soundhole spot may read differently than a peghead spot, depending on case tightness and sponge placement.


Buy a half dozen cheap digitals. Or at least three. If one reads bonkers, toss and replace.


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[ljguitar]

Originally Posted by epaul

...If you want to know how accurate they are, put them all on your kitchen table, and if one reads way off of the others, toss it and replace it.

Hi e-paul...
I'd recommend changing the battery first. I've found that when one of mine starts to go wonky (official terminology), I reset them.

Hygrometers don't tend to go totally dead suddenly, but just get 'weird' instead. This is true of my $40 one as well as my $6 ones.

I've had an inexpensive Walmart one ''freeze'', and then not move off the humidity and temp setting for a day. Pulled the battery, pushed all the buttons (to dissipate any residual electrical charge), let it sit for an hour, new battery and it still works several years later.

One of my others went 'off-road' as well till I renewed the battery.

Since I have multiple units in adjacent rooms, it's easy to tell when one begins to derail.

[Tanque Verde]

Originally Posted by epaul

If you want to know how accurate a particular hygrometer is, from a guitar perspective, use potassium carbonate, not table salt (sodium chloride).

Where might one conveniently purchase PC?

[epaul]

Originally Posted by cjd-player

...

You can check the accuracy of digital and other units with the salt bag test. But use potassium carbonate rather than table salt.
http://www.soapgoods.com/Potassium-Carbonate-p-719.html

The potassium carbonate gives a slat bag test reading of 43% relative humidity, which is more relevant to guitars than table salt and 75% RH. Also eliminates any discussion about whether corrections are linear over a wide RH range.

Buy 1 pound for about $10 (with shipping) and it will be enough to test your hygrometer every winter for several years.

Soapgoods is the same place I ordered my potassium carbonate from.

[epaul]

Originally Posted by ljguitar

...
I'd recommend changing the battery first. I've found that when one of mine starts to go wonky (official terminology), I reset them.

Hygrometers don't tend to go totally dead suddenly, but just get 'weird' instead. This is true of my $40 one as well as my $6 ones.

Good advice.

And, this good advice applies to tuners as well. If the tuner seems a little slower or wonkier than it used to be, or you think it should be, try putting a fresh battery in it.

Sometimes batteries last a little longer than they should.

[Simon Fay]

Just buy the Caliber III from Amazon. I have been using them for the past 8 years and about once a year I calibrate my Abbeon using the Potassium Carbonate test -- the Caliber III's are always within one or two points of accuracy. I have been including the Caliber III with my guitars and have bought dozens of them over the years. I do believe these hygrometers drift over time and so once every few years you should buy another one. Even the Abbeon needs to be calibrated regularly.

[epaul]

An informative link about hygrometer testing and RH levels of various salt solutions:

http://www.kingofthehouse.com/hygrometer/


I have had good luck with the Caliper III as well.

[golfreggie]

just ordered one from wal-mart for $8.94. Hope it is as good as I have heard on this forum
http://www.walmart.com/ip/AcuRite-Di...nitor/16888914

[newmartin]

went to the pet store and picked up one for a reptile tank. It is about 1.5" across and bang on to the meter on my humidifier which has a digital read out. $10 and it will fit in my case or sit on the shelf.

[Brant0086]

Why ?


Bryant

[weisser]

Originally Posted by Howard Klepper

The best are analog mechanical units made in Germany. So far as I can tell, all the popular digital brands come out of one or two factories in China and use the same sensors. IMO people's experience of accuracy with any of these brands is a matter of random chance.

The Abbeon sold by LMI is a very good one. Many consider this unit to be the standard for quality. LMI's price is as good as anyone's on it. About $165. They come up used regularly on Ebay.

The Taylor 5565 can be found discounted for about $60, and is also made in Germany. They don't guarantee the same degree of accuracy as the Abbeon (5% v. 3%). I see that it got a couple of negative reviews on Amazon, FWIW.

[edit] This site has the Taylor 5565 for $60. http://www.partshelf.com/taylor5565.html

Stan Jay at Mandolin Brothers has been using the Abbeon for years. With over $1,000.000 in inventory hanging on the walls, an accurate hygrometer is absolutely crucial. He even sells them.

The Abbeon was recommended to him by Bob Taylor.