How Does Humidity Affect Moisture Meter Readings?

Posted by Tom Laurenzi on Feb 17, 2018 1:33:00 PM

One question that moisture meter users frequently ask is “If humidity is the amount of moisture in the air, and moisture meters check the amount of moisture in something, can the humidity affect a moisture meter reading?”

Generally speaking, humidity does not directly affect the measurement of moisture to any significant degree. In other words, high humidity in the air doesn’t typically throw off the accuracy of a moisture measurement.

Why Humidity Doesn’t Affect Moisture Readings Directly


When using a pin-type meter, the material between the pins is used to complete a circuit, so moisture in the air will have little effect on the moisture measurement.

Pinless meters are also not very likely to have their moisture measurements affected by ambient humidity—assuming the material being tested is thick enough and the meter’s scanning plate makes solid contact with it. This is because the electromagnetic radio frequency “scans” the material being tested to a fixed depth in the area directly below the scanning plate.

So, unless the material being scanned is too thin, or the scanning plate is exposed to open air, a pinless meter won’t be scanning the humidity in the air at all.

How COULD Humidity Affect Moisture Readings, Then?

While the humidity doesn’t directly affect the moisture content (%MC) measurement of a moisture meter, there is a way that humidity can indirectly affect moisture measurements: damaging the scanning plate/electrode of the meter.

AdobeStock_48772600-355393-edited.jpegProlonged exposure to moisture can cause metal to corrode over time. In areas with extremely high humidity, the water in the air can speed up the corrosion process, damaging the testing medium and compromising future reading results. In this way, high humidity can impair the accuracy of a moisture meter.

So, while high humidity might not directly impact a moisture measurement, it may be important to track ambient humidity conditions and take the necessary precautions to protect your moisture meters from exposure to excess moisture.

If you find that the scanning plate or pins for your moisture meter have become corroded because of exposure to too much water for too long, the easiest fix is usually to replace the corroded testing medium. This is why it pays to use a meter that makes it easy to replace these parts and carry spare parts whenever possible.

Learn more about how you can use moisture meters by checking out our convenient Moisture Meters 101 guide for free! Or, if you need help finding the right moisture meter for your needs, contact Delmhorst directly!

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