Hygrometers and How To Use It

Hygrometers: Essential Tools

Hygrometers: Essential Tools for Managing Indoor Humidity

It can be dangerous for you and your house if your air is overly damp or dry. Fortunately, there is a small device that can assist you, a hygrometer.

For millennia, hygrometers have been used to measure humidity. Digital hygrometers are a valuable tool that every homeowner should have. The security of your home is crucial, and a hygrometer can help safeguard it.

You can need a hygrometer for a variety of reasons. It could be that you wish to check the weather before leaving home, tend to your greenhouse or garden, or maintain proper humidity levels in your home or business. Whatever the cause, investing in a high-quality hygrometer can help you get accurate readings. It will allow you to take advantage of the many hygrometer advantages you probably weren't aware of.


A hygrometer is a device that measures the relative humidity in a space. It comes in all sorts of styles and levels of complexity. Some hygrometers will display the relative humidity (the percentage of moisture in the air) or the exact amount of water vapour in the air (the absolute humidity). Some handmade hygrometers will tell you if the weather is damp or dry.

Hygrometers are a type of weather forecasting device. On the other hand, many homeowners use hygrometers to monitor humidity levels in their houses.

A hygrometer is a weather device that monitors the relative humidity of the atmosphere. Because temperatures determine the highest quantity of moisture in the atmosphere, reading on this gadget will reveal the relative saturation dependent on the room's current temperature. The reading is in percentage. The mechanical hygrometer or the wet and dry bulb psychrometer are available.

Essential Humidity Monitors


Hygrometers are handy gadgets that use pressure and temperature changes to calculate and calibrate pressure and temperature changes. When these percentages are added together, the amount of moisture in the air is calculated. In-office buildings and houses and manufacturing and industrial activities, a hygrometer is a useful tool. These places must ensure no fluctuation in humidity, as this could impair material manufacturing.


In terms of relative humidity, a hygrometer measures the humidity or moisture content of the air. This reading aids in determining the level of comfort associated with a certain air temperature. When the humidity is low, the air feels more comfortable in cold and hot temperatures. Humidity impacts plant and animal life, as well as architecture. Dew, fog, clouds, and rain are also more likely to occur when the air is humid.


The relative humidity is expressed in percentages. It's not the same as absolute humidity, the rate of water in the air. When compared to cold air, hot air can store more moisture. Moisture escapes the air as it cools. It generates small suspended droplets in clouds, fog, or droplets on surfaces like dew or fogged windows. As a result, the air can only contain a certain amount of absolute humidity at a particular temperature. The real total moisture is expressed as a percentage of the greatest absolute humidity.


Knowing how to read a hygrometer makes perfect sense, whether you'll use it for weather monitoring or to measure conditions in inside settings. These devices should be calibrated at least once a year to get the best and most accurate readings.

It is not difficult to read a hygrometer. However, the method varies based on the kind and model.

  • Dry bulb temperature
  • The temperature of the wet bulb
  • Wet-bulb depression (the difference between the first and second temperatures)


Two thermometers, one with a wet bulb and the other with a dry bulb, make up a psychrometer. A handle on a sling psychrometer allows the operator to rotate it in the air before taking readings. When the temperature rises above freezing, the water around the wet bulb evaporates, lowering the thermometer's temperature reading. When the temperature drops below freezing, the water condenses into an insulating coating of ice, giving the wet-bulb thermometer in an analogue hydrometer a greater temperature reading than the dry bulb thermometer.

To calculate relative humidity with an analogue hygrometer, you need a psychrometric chart. A row of dry bulb readings and a column of wet bulb readings make up this chart style. Cross-referencing the wet and dry bulb temperatures yields relative humidity.

The separation of the thermometers from radiant heat and appropriate airflow over the thermometer bulbs are critical to the accuracy of an analogue hygrometer. These parameters are particularly important in low-humidity situations when the wet-bulb temperature is near the dry-bulb temperature. For low humidity, the most accurate analogue hygrometers that use wet bulb thermometers could have an error rate of up to 5%.

How to Read Analog Hygrometer

To read the result, look at the graph on the device's face and read down, starting with the wet-bulb depression and ending with the dry-bulb temperature. Calculate the relative humidity of the space by finding the intersection of the numbers. It's best to use percentages to express the ultimate solution.


Digital hygrometers employ a composite coil to record humidity, whereas resistive or capacitive sensors are used in their analogue counterparts. This article will go over what you need to know about digital hygrometers.

The only difference is that you must calibrate analogue hygrometers before each reading for accuracy. Then, digital hygrometers can be read without any prior calibration.

Because they can monitor the relative humidity and temperature changes quickly, digital hygrometer readings are often more accurate than analogue metre readings. Still, they cannot offer specific rainfall data as analogue metres can.

How to Read Digital Hygrometer

For digital hygrometers, a distance of roughly 3.3 feet (one metre) from the ground is required. Allow at least three minutes for the gadget to detect the temperature of the air properly. You won't have to do more computations since the instrument will take care of everything.


Indoor Humidity Trackers



If you want your hygrometer to provide reliable readings, you must ensure that it is properly calibrated. A hygrometer is important if occasionally ignored, a component in any self-respecting humidor. A properly calibrated and accurate hygrometer is essential even with the greatest humidor.

In addition to the hygrometer itself, calibrating a hygrometer necessitates specialised equipment. A plastic soda bottle cap and an airtight food container large enough to carry the hygrometer are included. A tiny amount of table salt, water, and a flat head screwdriver that suits the hygrometer's calibration screw are also required for hygrometer calibration.

Analog hygrometers need calibration every six months, as they tend to lose their calibration over time. Digital hygrometers are usually factory calibrated and cannot be adjusted by the user. Wrapping the entire hygrometer with a damp cloth and adjusting the hygrometer to read 96 per cent is a faster but less precise technique of calibrating the hygrometer.


Pour a teaspoon of salt into a clean, dry soda bottle cap as the first step. Add enough water only to moisten the salt without causing it to dissolve. Then, it would help if you positioned the bottle cap and hygrometer as near together as feasible in the plastic container. To guarantee that the air in the container is at normal pressure, it would be best to seal the lid without pressing down.

After eight hours, you can open the container and remove the hygrometer. If the hygrometer doesn't show a reading of 75 per cent after reading the humidity level, it can be changed. This method of calibrating a hygrometer is based on the fact that the moist salt provides a relative humidity of 75% when the test is done correctly.

The calibration screw is used to adjust the hydrometer. To increase the hygrometer's reading, turn the calibration screw clockwise. Then to reduce the hygrometer's reading, turn the calibration screw counter-clockwise. If the hygrometer reads 65 per cent after the test, add ten per cent to the humidity readings on that hygrometer. Any difference from 75 per cent should be documented and applied to future measurements if the hygrometer does not include a calibration screw.


You can need a hygrometer for a variety of reasons. It could be that you wish to check the weather before leaving home, tend to your glasshouse or garden, or maintain proper humidity levels in your home or business. Whatever the cause, investing in a high-quality hygrometer can help you get accurate readings. It will allow you to take advantage of the many hygrometer advantages you probably weren't aware of.

Prevent Health Problems

Exposure to humidity levels that are too low can be hazardous to one's health. As a result, maintaining the proper humidity level is critical. When you have too much moisture in your home, the chances of germs and mould growth are great. Some of these products are poisonous and deadly to people and pets alike. It will help if you exercise utmost caution, small kids. Maintain a minimal amount of humidity to avoid creating an ideal environment for germs to thrive.

Note that dry air might be an issue as well. It can cause sinus problems, itchiness on the skin, coughing, and other symptoms. Because you'll have to keep your ventilation at high levels with dry air, many allergens will be able to travel freely in the air. As a result, don't retain humidity at dangerously low levels. Once you have a hygrometer, setting it to the Goldilocks zone will keep the humidity levels in your home at a comfortable level, not too high or too low. It will be the ideal level for your family's comfort and safety.

Boost Indoor Comfort

The relative humidity value is the finest for great outdoor observations. It's also true when it comes to the interiors. If you spend a lot of time indoors, a hygrometer will assist you to know when to change the temperature to a comfortable level for you and your family. A good hygrometer will show you how much moisture is present so you can take the proper action, such as turning on the ventilation or heating system. Because humidity directly impacts your comfort level, strive to keep it at the suggested level of 40-50 per cent. Using dehumidifiers and humidifiers, you can always maintain a suitable indoor temperature, despite the weather outside.

Beneficial to Plants

Whether you have a glasshouse or a regular garden, it's critical to watch the humidity levels to ensure healthy plant growth. Maintaining humidity levels in a glasshouse can be particularly difficult. On the other hand, getting an accurate hygrometer can make things easier. Plant growth might be hampered by dry air. It has the potential to dry out some of the plants. Problems like fungal and root rot can arise when moisture levels are too high. When humidity is regulated appropriately, you can readily avoid such issues.

Predicts Weather

A hygrometer is a widely used tool to track weather patterns and predict what will happen next. Humidity can aid weather forecasting by combining barometric pressure, wind readings, and temperature. You may confidently plan activities such as outdoor walks and travels with such forecasts. As a result, a hygrometer can assist you in making vital judgments.


Precise Hygrometer Tools


HVAC Shop Hygrometers

Since Leonardo da Vinci initially invented hygrometers in 1480, they have evolved significantly. Having a hygrometer in your house or office is essential. If you don't already have one, obtain one and enjoy the benefits listed above and others.

Browse the available hygrometers in HVAC Shop Australia!