Calibrating your hygrometer regularly is essential for accuracy in most hygrometers, and capacitive hygrometers have only a 2-percent margin of error when properly calibrated. The error rate increases to 5 percent when not calibrated.
You can calibrate your hygrometers with a psychrometer, but another option is to place a teaspoon of salt in a bottle cap and add a few drops of water to get the salt wet but not dissolved in a solution. Place the container in a plastic bag with the hygrometer and some air, and seal the bag. Allow the hygrometer to stabilize for six hours before taking a reading. You should get 75 percent. If not, you can adjust some hygrometers to exactly 75 percent or remember to add or subtract the difference when taking future readings. You can also wrap a moistened cloth around the hygrometer and seal it in a bag for six hours. You should get a reading of 95 percent.
Hygrometers are versatile for many home, business and manufacturing uses. You can get battery-powered, mechanical or advanced technologies to measure humidity and temperature. If you choose more accurate instruments, then chances of breakage increase, so select a hygrometer with a good warranty. Each person has his or her own reasons for measuring humidity, but you have a range of choices from simple to complex. From curing meats and sausages to ensuring safe surgical environments, hygrometers determine moisture contamination, optimal humidity levels, best manufacturing practices and energy-saving strategies for HVAC equipment.