Calibrating a hygrometer is essential to ensure accurate humidity readings. Here’s a guide on how to master hygrometer calibration:
Things you’ll need:
A calibration kit (salt test or other calibration solutions)
A resealable plastic bag
Distilled water
Small cup or container
Hygrometer calibration steps:
Salt test method (recommended for analog and digital hygrometers):
Prepare the calibration kit:
Obtain a calibration kit or create a saturated salt solution by mixing salt and water to form a paste. The type of salt recommended is sodium chloride (table salt).
Create a controlled environment:
Place the hygrometer, a small cup, and the saturated salt solution inside a resealable plastic bag.
Set up the calibration:
Add a small amount (about a teaspoon) of the saturated salt solution into the cup.
Seal the bag:
Seal the bag tightly, ensuring that it is airtight to create a controlled environment.
Wait for calibration:
Leave the sealed bag undisturbed for around 6-12 hours.
Check and adjust:
After the set time, check the hygrometer reading. It should show approximately 75% rh (relative humidity). If the reading is off, use the adjustment screw or digital calibration settings (if available) to correct it.
Additional tips:
Use distilled water to create the salt solution for accuracy.
Ensure the hygrometer is clean before calibration.
Repeat the calibration process periodically for consistent accuracy.
Digital hygrometer calibration:
Some digital hygrometers come with built-in calibration options. Refer to the manufacturer’s instructions for specific steps, which might include accessing a calibration mode or using specific buttons to adjust the reading.
Analog hygrometer calibration:
Analog hygrometers often have an adjustment screw on the back. Use a small screwdriver to turn the screw until the correct humidity reading is achieved during the salt test calibration.
Verifying calibration:
After calibration, it’s a good practice to verify the accuracy of your hygrometer periodically. You can do this by comparing its readings to those of another calibrated hygrometer or a more accurate reference instrument.
Ensuring your hygrometer is accurately calibrated is crucial for maintaining proper humidity levels in environments where accuracy matters, such as in sensitive equipment storage, instrument rooms, or cigar humidors.
