How do I choose a moisture meter?
There are two types of moisture meters available, the pin and pinless style. The pin type uses a pair of pins that are pressed into the material. A voltage is applied to the pins via a battery, and the resistance between the pins is measured. You tell the meter what type of material you are measuring (i.e. plaster, wood, etc.), and the meter converts the resistance into moisture content in percent.
The pinless style uses a capacitance measuring device, so the device is held above the surface of the material, and the effective capacitance is converted to moisture content. I understand that the pinless style is quicker, and can be used to rapidly located suspect areas. The pin style is then typically used in specific areas since it is more accurate.
Costs range from $50 to several thousand dollars, depending on the required accuracy, the types of materials to be tested, and the ability to interface with a laptop to store results.