A relative humidity meter is a device used to measure the relative humidity (RH) in the air. RH is a measure of the amount of water vapor in the air compared to the maximum amount of water vapor that the air can hold at a given temperature.

Importance of Measuring Relative Humidity

• Water Damage: Excessive moisture in the air can lead to water damage to buildings, furnishings, and other materials.
• Health: High RH levels can promote the growth of mold and mildew, which can cause respiratory problems.
• Comfort: RH levels that are too high or too low can make people feel uncomfortable.

How Does a Relative Humidity Meter Work?

Relative humidity meters use a variety of methods to measure RH. Some common methods include:

• Resistive: These meters use a sensor that is coated with a material that changes resistance when it absorbs moisture.
• Capacitive: These meters use a sensor that consists of two metal plates separated by an insulator. When moisture is present, the capacitance between the plates changes.
• Psychrometer: These meters use two thermometers, one of which is covered in a wetted wick. The difference in temperature between the two thermometers can be used to calculate RH.