Best Instruments For Measuring Humidity

Hygrometers, also known as humidity sensors and Psychrometers, are precision instruments used to measure humidity. These instruments measure the relative humidity of the atmosphere. Here you need to note that the relative humidity is the amount of vapor present in the air compared to the highest possible amount of vapor.  

Why Measuring Humidity is Important?

Measuring the water vapor or humidity is crucial for various construction purposes. Inappropriate humidity in the soil, air, and various confined spaces might bring hazardous results. In the construction of buildings, ill-suited humidity levels can be dangerous for inhabitants. They can also lead to poor storage conditions.

Furthermore, high humidity levels can lead to the formation of fungi, viruses and various other pollutants. On the other hand, problems like electrostatic discharge, skin irritation, and breathing problems for people due to low humidity levels. Humidity sensors are also commonly used in greenhouses, wine cellars, cigar warehouses, manufacturing units, and museums.

Various Types of Hygrometers

  • Psychrometers - In this hygrometer, there are two thermometers; one has a wet bulb while the other one has a dry bulb. When there is evaporation in the wet bulb, its temperature drops lower than that of the dry bulb. This difference in the temperature of both the bulbs is caused by the humidity present in the air. Therefore, this type of hygrometer is ideal for measuring humidity in the outdoor areas and also in the areas that are used for dry storage.
  • Dew point hygrometers - This hygrometer is used to measure the level of moisture present in the air. This instrument is ideal for measuring the minimum amount of water vapor present in the atmosphere. Therefore, it is the most precise instrument for measuring humidity.
  • Electrical hygrometers - This instrument uses either capacitance or resistance to measure the humidity present in the air. Therefore, this humidity sensor can be resistive or capacitive. The capacitive hygrometers have air between two separate metal plates. The moisture in the air affects the ability of the plates to store the static electric charge. On the other hand, a resistive hygrometer consists of a ceramic piece that is exposed to the air. As the humidity increases, more water vapor condenses under the ceramic particle. This ultimately leads to the change in the resistance.

Factors to Consider While Buying a Hygrometer:

Selecting a suitable hygrometer can be a daunting task because there is a huge variety of measuring instruments. However, a prospective buyer needs to consider the following major factors before making a purchase:

  • Requirements - The first thing to consider is the purpose of buying the instrument. A hygrometer used for domestic purposes does not need to be 100% accurate. Moreover, you need to figure out if you will be using the humidity sensor in various rooms or the areas that are hard to reach, such as attics. In addition, to measure the humidity in areas outside a house, it is ideal to use a home weather station.
  • Specification - Accuracy is a crucial factor for calculating humidity. Therefore, you need to consider the +/- RH ratings before purchasing. In addition, buyers also need to consider the user interface, data logging, power source, and access to previous data to make a smart purchase. If you need to monitor the humidity of various places at a time, you need to look for a hygrometer that can connect to multiple sensors as one system. Moreover, instruments that help calculate humidity remotely are beneficial.
  • Cost of the instrument - There are numerous instruments available in the market. However, you need to set your budget and requirements first before searching for a hygrometer. This will save you most of your time and energy.

Which are the 3 Best Hygrometers in India?

Sr. No.




MECO 920 - Digital Thermo Hygrometer

± 0.5 degree C - ± 1.0 degree C


Testo 608-H1 - Operating Temperature 0 to +50°C, Thermo Hygrometer

±0.5 °C (at +25 °C)


Metravi TH 04 - 0 Deg C Digital Temperature and Humidity Meter

+/- 5 Deg C

  1. MECO 920 - Digital Thermo Hygrometer

It accurately calculates the humidity in a room or other outdoor environment. The LCD screen clearly displays the result. Moreover, it has multitudinous functions for the convenience of users. It is designed with a temperature range of -20°C to 60° C and has an accuracy of ± 0.5° C - ± 1.0° C. It is a lightweight and portable instrument.

Accuracy: ± 0.5 degree C - ± 1.0 degree C

Power: 1.5 V AAA x 2 Batteries

2. Testo 608-H1 - Operating Temperature 0 to +50°C, Thermo Hygrometer

It is an ideal instrument for heavy-duty usage for indoor humidity calculation. It comes with a hanging and standing bracket that helps in either placing it on a table or hanging it on a wall. The optimum sized LCD clearly shows the humidity, temperature, and dew point results. It has an NTC temperature probe for performing precise and accurate temperature measurements. It has an increased battery life of 1 year, and it notifies the users before the battery dies.

Accuracy: ±0.5 °C (at +25 °C)

Humidity - Capacitive Resolution: 0.1 %RH

3. Metravi TH 04 - 0 Deg C Digital Temperature and Humidity Meter

This instrument calculates the humidity of the soil, air and other confined spaces. It uses condensation temperature, also known as the dew point or changes in electrical resistance or capacitance, to calculate the humidity differences. It is ideal for museums, incubators, greenhouses, humidors, and saunas. It is also used to protect wooden instruments like guitars, pianos, violins, etc., from damages caused by improper humidity.

Accuracy: +/- 5 Deg C

Relative humidity: 10 to 90 per cent RH

Hygrometers are crucial devices that calculate the amount of moisture present in the atmosphere. They are used in various places like homes, industrial areas, office buildings, etc. now that you know what factors that need to consider before buying a hygrometer, go on to make the smartest decision.