Deciding which hygrometer to use depends on what you are using the humidity measurements for. If you are just curious about humidity in your home, you can make a very simple hygrometer using the wet/dry bulb thermometer system. If you need to accurately assess the humidity of your environment for preservation or scientific reasons, purchasing a proper hygrometer is a better idea. Consider the following questions before you purchase your hygrometer:Does it need to survive in extreme hot or cold temperatures?
Does it need to run on battery power or will it be near a power outlet?
Do you need an alarm to detect if the environment goes above or below a certain percentage of humidity?
Is it easy to re-calibrate?
Is it expensive? Does it require a lot of maintenance?
Is it easy to understand and use?;
, Once you have chosen your hygrometer, you need to pick a good location to keep it. Humidity measurements are dependent on temperature so choose a location that does not experience frequent temperature fluctuations.Place the hygrometer in a location that has a consistent temperature similar to the rest of the room.


Avoid placing the hygrometer near doors, heaters, humidifiers, or air conditioners.
 To get the most accurate readings, you must leave the hygrometer in your chosen location for a few hours so it can reach the ambient temperature of the environment. Taking a reading just after placement will likely result in an inaccurate reading.
 If you are trying to determine if you have humidity fluctuations in your home, take readings every few hours or days. This will allow you to chart the humidity levels over time.


Note that as air gets warmer, it can hold increasingly more moisture. The higher the temperature, the higher the relative humidity.
 Typically, a hygrometer needs to be calibrated about once a year. Calibration involves comparing the readings of your instrument to that of a calibrated reference sample and adjusting yours to match. Calibration is most important for scientific or research work. In this case, the hygrometer must be sent to a special facility for calibration.


If you are using a homemade hygrometer, you can leave your hygrometer outside and check it against the reported readings for the day.
Choose or make a hygrometer.
Select a representative location for measurement.
Acclimate the hygrometer to the environment.
Take regular measurements of humidity.
Calibrate the hygrometer, if necessary.
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