Hygrometers are used in commercial and residential spaces to ensure comfort, reduce energy use, prevent condensation mold and allergies and control the bad effects of dry air, which include breathing difficulties, itchy skin and static-electricity sparks. Certain kinds of equipment, storage areas, basements and attics develop problems when the air is too moist or too dry. Condensation and moisture lead to mildew, musty smells, wet and dry rot and problems with sensitive electrical equipment.
Saunas can become uncomfortable unless proper humidity is maintained. If you are storing old books, cigars and food, the right humidity levels prevent spoilage and damage. Guitars and violins can crack when humidity levels drop too low. Monitor these instruments inside their cases, and don’t let humidity drop below 40 percent. Cigars need 70-percent humidity to stay fresh, so place a hygrometer in the humidor to monitor moisture. Plug-in humidity controllers use hygrometers to monitor moisture and turn on a humidifier or dehumidifier when humidity gets outside a preset range. Terrariums for plants or reptiles need the right moisture environment, so use a digital probe to measure humidity so that reptiles and plants don’t die.
A simple pine cone can give you some information about humidity because it closes when the air is humid and opens when ambient air is dry. You can make a simple hygrometer with a pine cone, but it won’t be very accurate and takes some time to respond to humidity changes. Whether for good or ill, people today expect results instantly, and most people don’t want to fool with making their own hygrometers or calibrating psychrometers with wet cloths and thermometers. Electronic hygrometers and other technologies allow you to monitor enclosed spaces and indoor areas. You could even create your own weather station and install a wireless sensor to display outdoor temperature and humidity.