What Moisture Meter is the Most Accurate?
A few years ago, on a wood flooring inspection, I used two different meters and got two different moisture readings – testing the same boards.
Is this normal? Let’s find out!
First, let’s look at the technology to answer this question.
There are two basic types of electronic devices on the market for measuring moisture in wood – pin and pin-less. A third type measures relative humidity (%RH) primarily in concrete. Be sure you’re using one meant for wood flooring.
“Non-destructive” aka pinless or surface meters use a flat sensor pad that measures 3/4 inches into the flooring. The science – the meter measures the electromagnetic frequency of the returning radio waves from those transmitted from the unit.
“Destructive” or pin meters measure electrical resistance between two conductive pins inserted into the wood. Pin meters with an extension attachment measure up to several inches.
Did you know that moisture meters don’t actually measure moisture?
How do these qualify as testing moisture?
The answer is gravimetry!
Gravimetric testing determines the gravity or weight of water in a material (such as wood) by evaporating out the water. The wood first is weighed, then evaporated, and then weighed again. This data calibrates the meters so that they can accurately measure the “moisture equivalence” by species.
This is why proper species calibration is essential for each electronic device.
Do all brands of moisture meters use this technology as a baseline?
Reputable manufacturers include this in their documentation. Consult their website to confirm their requirements and specifications. A few brands we recommend include Lignomat, Delmhorst, and Wagner.
To summarize, the accuracy of a meter is determined by how well it is calibrated, not by if it is pin or pin-less. The next important thing to consider is what you are testing.