How To Care For A Hygrometer (Explained)

by Alex Kountry
Updated on

A hygrometer is a great tool to have in your house and can serve various reasons including monitoring humidity levels in your house, your greenhouse, house plants, and instrument case to mention a few.

However, it is important that you always keep your hygrometer clean and safe.

There are various ways of caring for your hygrometer including keeping it in a safe dry place, changing the sensor from time to time, cleaning the filter cap etc.

In this article, we will discuss ways to care for a hygrometer, how to clean the sensor, how you know if your hygrometer is working among other questions.

How Do You Care For Your Hygrometer?

How To Care For A Hygrometer
  • Clean The Filter Cap

The filter cap of your hygrometer has to be good and kept clean for a long time performance of the device.

Filter caps protect the sensing head from dirt or dust. The filter cap can get clogged up or dirty in the cause of using it.

Always ensure you gently clean the cap from time to time to get rid of dust particles that might have garnered there.

Once you notice your device is giving longer response times then the filter cap is polluted already and this might get to the sensor head.

Replace the filter cap for proper working again.

  • Store in a Dry and Clean Place

Your hygrometer should be stored in a dry and clean place this will help to keep the device away from dust and dirt that can affect the workings of the machine.

Also the device should be kept away from water. 

Even if you are using the device outdoors, place it in a safe place away from harsh elements such as heat and rain

  • Recalibrate from Time to Time

Some hygrometers come factory calibrated and you do not have to calibrate it byself.

However, in the course of use, temperatures beyond the -4F to 140F range can cause calibration and sensor signals to be thrown off. 

This means you might have to adjust the calibration from time to time to keep the readings accurate.

Also, to prevent inaccurate readings, keep air exposure to the sensors at a minimum. This is because contaminants and chemical factors can affect the calibration..

  • Keep Hygrometer in Protective Packaging

Some hygrometers come in a box package, you can keep them in such packages to ensure they are safe from dust and other contaminants.

If you do not have the protective packaging anymore, you can cover the hygrometer in a sheeny material as that will also do the job perfectly. 

  • Replace RH Sensors From Time to Time

Over time and due to exposure RH sensors can collect tiny contaminant particles.

The accumulation of material deposits eventually alters the sensor material’s properties, calibration, and response time. This combined with aging of the sensor can lead to inaccuracy in readings. 

The lifespan of a RH meter sensor is entirely dependent on how well the device is treated and handled, as well as the frequency with which it is used and the correct initial calibration.

If you notice the inaccurate readings are coming from your sensor, then you would have to replace the RH sensor. 

Here is an article I wrote on are hygrometers accurate

How Do You Clean A Hygrometer Sensor?

The hygrometer sensor is the tool that actually measures the humidity and temperature levels before the device calculates.

You are not supposed to touch or wipe a hygrometer sensing head as this can introduce further contaminants to the sensor.

I’ll outline a few steps for you to properly clean your hygrometer sensor:

  1. If it is an electrical device, disconnect from power supply and if wireless, remove the batteries.
  2. Wipe clean other parts of the hygrometer including the cable and sensing probe (stick to water or alcohol isopropyl)
  3. Unscrew the filter cap. This should be done gently to avoid touching the sensor.
  4. Get 2 glass vessels ready. Fill one with isopropyl alcohol and the water with clean water.
  5. Hold on to the sensing probe and place the sensor head in the alcohol. Shake the probe gently in the alcohol. This should be done for 3 minutes, however in cases of heavy dirt deposits keep it in till it’s all clean.
  6. Once it’s clean, transfer the sensor head to the clean water and hold for 3 minutes.
  7. Let the sensor air dry for about 30 minutes
  8. Replace the filter cap with a new one and gently screw back on to the sensor.  

How Do I Protect My Humidity Sensor From Breaking?

Like I mentioned earlier, there is a high possibility of your sensor giving incorrect readings when it is exposed to contamination and chemical factors.

Your sensor head should not be exposed or near the following items:

  • Plastics
  • Polystyrene
  • Acetate
  • Adhesive tape and chemicals
  • PVC
  • Delrin

High levels of chemical exposure, in particular, can permanently damage your meters’ sensors by affecting it’s sensing polymer. 

When those chemical and hazardous substances settle into the sensor can cause calibration to shift and the meter’s sensitivity to suffer.

Extreme exposure can cause permanent damage.

To protect your sensor ensure it is only exposed to elements within a short period of time.

Store the hygrometer in a protective packaging so the sensor is protected. Do not touch or clean your sensor or let it contact any material so it can give you accurate readings.

Here is an article I wrote on the best hygrometers with clock

How Do I Know If My Hygrometer Is Working?

Sometimes your hygrometer might give incorrect readings.

This could be bad if  you are using it for a sensitive purpose such as checking your greenhouse or cigar humidor sensitivity.

There are ways you can use in testing the accuracy of your hydrometer but I’ll be explaining the salt test in this instance.

This test is simple and can be done with a few household items. I’ll outline the steps to take to know if your hygrometer is working accurately:

  • For this test get together some table salt, a Ziploc bag, a small cup and water.
  • Pour the salt into the cup till it’s full and some water till it’s a thick sludge. You should be careful so the salt doesn’t dissolve.
  • Place the cup and your hygrometer into the Ziploc bag and zip it up. Place it in a cool place where it won’t be disturbed during the test.
  • The waiting time is 6hours for the hygrometer to measure the humidity in the bag.
  • An accurate hygrometer should give you a humidity level of 75% after 6hrs. If the humidity level shown on the hygrometer is either higher or lower than 75% you will have to calibrate the hygrometer.

Hygrometer readings can get inaccurate over time so it is advisable that you carry out the test every 6months.

Where Should The Hygrometer Be Placed?

The ideal placement for your hygrometer is dependent on the location whether indoors or outdoors.

The placement of your hygrometer is important as it can influence the accuracy of the readings.

Some ideal placements for hygrometers in the house include:

  • The kitchen
  • Bedroom
  • Bathroom
  • Basement
  • Study/Office
  • Living room

Out of all these options, the kitchen is often the most recommended as it has a better airflow. Wherever you are placing your hygrometer should not be too hot or cold.

It is advisable not to place the hygrometer near a window or close to electronics as this can distort it’s readings. 

For outdoor hygrometers it is advisable to place them on the ground in a shaded place away from direct sunlight and rain.

The standard height from the ground is often 1.5 meters. 

How Do I Know If My Hygrometer Is Broken

You can determine if your hygrometer is broken using the salt test outlined above and this is particularly good for digital hygrometers.

If you use an analog type, the wet towel test will work for you. Soak a small hand towel and wrap it around the hygrometer.

Leave it for 30 mins. After that period, if the needle shows any figure other than 100% the hygrometer is broken and needs to be recalibrated. 

Have it in mind that hygrometers often require calibration more often than we think. Carry out the test regularly to ensure you are getting correct readings.


If you have not been taking care of your hygrometer, you should not be surprised if you get inaccurate readings.

Your hygrometer when exposed to dirt can start to give incorrect humidity readings.

Always keep your hygrometer in a clean dry place, put it in a protective packaging and recalibrate from time to time.

Tests that you can use in knowing if your hygrometer is broken include the salt test and the wet towel test.

Once you care for your device, you will be able to use it for quite a long time.

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About the author

Alex Kountry

Alex Kountry is the founder of HayFarmGuy and has been a backyard farmer for over 10 years. Since then he has decided to write helpful articles that will help you become a better backyard farmer and know what to do. He also loves to play tennis and read books


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