????? 1 .Decide if the digital hygrometer will be for indoor or outdoor use. Outdoor hygrometers are waterproof, rugged and designed for extreme swings in humidity. Indoor hygrometers are often (but not always) designed for greater accuracy.

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???? 2 .Decide what level of accuracy is required. The accuracy of hygrometers varies by model and price, and margin of error varies from 1 to 5 percent. For most applications a high degree of accuracy is not needed, but monitoring of highly sensitive objects (such as many museum artifacts) will require great accuracy. To improve accuracy, use a psychrometer to calibrate hygrometers.

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???? 3 .Decide if the hygrometer will be for spot-checking conditions or constant monitoring. Hygrometers used for spot-checking are very different than models designed for constant monitoring. Dataloggers are special types of digital hygrometers that record constant data (at user-specified intervals), which can be downloaded into a computer.

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