Instruments for measuring indoor air humidity: types + recommendations for selection

A comfortable stay in an apartment is possible after ensuring a comfortable microclimate suitable for residential premises. The climatic conditions in the room depend on the temperature and humidity of the air, so these indicators must be carefully monitored using special devices.

Thus, a thermometer is used to determine the temperature in a room, and a device for measuring air humidity is called a hygrometer. The principle of operation of a thermometer is familiar to everyone, but not everyone knows how a moisture meter works and how to choose the appropriate option.

Let's look together at the existing types of these devices and the features of their operation in this material. Let's also talk about the rules for choosing a suitable hygrometer.

How is air humidity measured?

You can find out the amount of moisture using available means: a lighted candle, a fir cone, a glass of water, or the condition of the leaves of a homemade moisture-loving plant. Such methods have been used for a long time, but they determine only approximate values.

Accurate readings can be obtained with a regular thermometer. This method is long and not very convenient, since it requires compliance with certain instructions, without which the data obtained will have a significant error.

Modern moisture meters are safe and fit harmoniously into the interior.Therefore, they can be used in any room to create a comfortable microclimate

To objectively measure water vapor in the air, special instruments are used that convert data on temperature and vapor concentration.

Such devices include:

1. Hygrometers.
2. Psychrometers.

Devices with different operating principles show values ​​with varying degrees of error. Some of the devices provide accurate data on the moisture content in the air, others allow for error.

There are instruments that record absolute values, and there are meters that reflect relative values. Therefore, before choosing a hygrometer, it is necessary to study the operating principle of the devices and take into account the conditions in which the device will be used.

The absolute value reflects the weight of water vapor in a cubic meter of air. The value is indicated in grams, kilograms per cubic meter. Such a value will not tell an ordinary person anything, so the unit of measurement is usually considered to be relative air humidity.

Relative humidity is the ratio of steam and air. The maximum possible amount of vapor in the air is 100%, the remaining values ​​are displayed relative to the maximum value.

To calculate the relative amount of moisture in the air, each device is equipped with a temperature sensor. Some devices broadcast additional temperature data, which is convenient since you don’t need to buy an additional thermometer

According to SNiP 2.04.05-91 relative air humidity should remain between 30-60%. In climatically humid areas, with outdoor vapor content greater than 75%, the values ​​will be slightly higher.

Operating principle and types of devices

The operation of hygrometers is based on variations in the physical parameters of various materials. When the amount of vapor in the air changes, the properties change: density, weight, length and other operating parameters of the substances. By recording changes in the physical characteristics of materials, it is possible to draw conclusions about the amount of vapor in the air.

Hair and film moisture meters

The simplest mechanisms of devices, analyzing the physical properties of materials, make it possible to accurately determine the amount of vapor in the air.

Hair device consists of synthetic degreased hair, base with scale, pointer and pulley. When the vapor increases or decreases, the tension force of the hair changes, the pulley rotates, changing the position of the arrow on the scale with values.

Rare and exclusive models of hair hygrometers operate exclusively according to the laws of mechanics, and therefore do not require an external power source

This meter operates in the range from 30 to 80%. Nowadays it is practically not used, since there are other models that have a larger range of operation.

IN film moisture meter An organic film attached to the pulley acts as a sensitive element. When the humidity indicator changes, the film tension increases or decreases, which leads to the movement of the pulley, which changes the angle of the arrow.

The pointer moves along the arc-shaped dial, showing the percentage of air humidity in the room.

Both mechanisms operate according to the laws of mechanics, so they can accurately measure moisture in rooms where the temperature is low, down to 0 ° C.

Weight and condensation meters

By using weighing hygrometer absolute air humidity can be determined.This device is used for laboratory experiments, so it is not suitable for indoor use at home.

Condensation meter summarizes the most accurate data. The design of such a device consists of a flat surface on which moisture settles, a thermometer that determines the moment of condensation formation, and a beam of light that detects the appearance of the first condensation. The operating range of the meter is from 0 to 100%.

The condensing device has large dimensions. To activate the device, a rubber bulb is used, so such moisture meters are used only in laboratories

These mechanisms generate results with high accuracy, which is necessary for research, but not as home air humidity meters.

Mechanical and electrical devices

Mechanical or a ceramic moisture meter works through electrical resistance of the mass. Since the ceramic mass contains silicon and kaolin with metal particles, the resulting mixture changes resistance after a change in air humidity.

Due to this, with different steam contents, the arrow on the device changes position, reflecting the air humidity.

This operating mechanism allows ceramic devices to be made compact, which is why they are in demand for measuring air humidity in the home.

Electronic or room hygrometer - a modern high-speed device for determining indoor air humidity.

The following operating principles can be used in the design:

• measurement of electrical conductivity of ambient air;
• optoelectronic method, with dew point measurement;
• measurement of electrical resistance of polymers and salts;
• analysis of condensate capacity.

The digital moisture meter works using microcircuits, so calculations are made within a few seconds, and the output data has minimal error.

Accurate readings from an electronic hygrometer are possible in the absence of a draft. Some models allow fluctuations of up to 2 m/s, to take this into account, you must first read the technical documentation

When determining air humidity with devices of this type, it is necessary to take into account the ambient temperature. The slightest deviations from stationary conditions affect the final indicators, therefore, before direct measurement, street doors must be closed for 15 minutes.

In addition to temperature fluctuations, the operation of devices is affected by the proximity of heating devices. Therefore, when placing hygrometers of any type, take into account the proximity of radiators and place them on the opposite wall or table, located at a considerable distance from the heaters.

Operating principle of the psychometer

Another device for measuring indoor air humidity is psychometer. The mechanism of operation of psychrometric devices is based on the use of physicochemical properties of liquids.

For measurement, two degree tubes with liquid are installed on the device, one of which is wrapped in a wet cloth. When moisture evaporates, the temperature on the wrapped tube is lower than on the dry one.

Mercury and toluene are used as liquid materials for filling psychrometer thermometers. A device with toluene is less dangerous for household use

To obtain the result, you need to look at the air temperature on a thermometer that is not wrapped in fabric, and calculate the difference in liquid readings between both tubes.

Next, in the first column of the table of values, find the air temperature according to the thermometer. Find the difference in values ​​in the top line. The number at the intersection of the column and row is an indicator of humidity.

There are three types of psychrometers:

1. Stationary. A simple device consisting of two thermometers enclosed in a meteorological flask. One of the thermometers interacts with a damp cloth, due to which the liquid changes its physical and chemical properties and a difference in degrees appears. The results are calculated from the table.
2. Aspiration The psychrometer is similar to a stationary one, the difference is that an aspirator fan is installed in the protective housing to move compressed gas. A kind of vacuum creates conditions for obtaining the most accurate indicators.
3. Remote the device can be manometric or electrical. The design contains pressure gauge thermometers or thermistors, which change resistance depending on the state of the external environment. The finished results are displayed on the digital display of the device.

Psychrometric devices undergo standardization and verification, so the output values ​​can be considered the most accurate.

Stationary instruments for measuring the amount of moisture in the air are mounted and tabletop, so they will fit harmoniously into any interior.

What to look for when buying?

Indoor models of devices for measuring the amount of moisture in the air include mechanical and electronic hygrometers. They have a compact design, are safe for others and produce minimal errors in calculations. To support the design idea, modern devices have a laconic design.

Criterion #1 - operating principle

Mechanical and digital hygrometers have a number of advantages that can influence the choice of device.

The advantages of mechanical models of moisture meters include the following:

• the operation of the device does not depend on external power sources;
• they are easy to use since minimal additional adjustment of the necessary operating parameters is required;
• the cost of a mechanical hygrometer is slightly lower than an electronic one.

Digital models are made in the form of folding, portable gadgets.

In addition, the advantages of electronic models include:

• high speed of results;
• smaller reading error compared to a mechanical device;
• The output data is subject to further processing due to the presence of built-in internal memory.

Some electronic moisture meters combine several devices at once: hygrometer, clock, calendar, thermometer, barometer, dew point meter. Therefore, if a device performs several climate functions, this is stationary weather station.

Some moisture meters have a built-in alarm system that triggers when the steam level drops or rises between 30 and 60%. Such a device should be in homes where the climatic conditions of the region suggest high humidity or dry air

For the comfort of the child and parents, a hygrometer can be built into the baby monitor. This device has great functionality and an alert system.

The latest models are equipped with a Wi-Fi module to display information about the weather in the region by receiving data via the Internet.

Modern models of hygrometers are designed for specific specifics of work, so in order to accurately measure the air humidity in a room, apartment or other premises, you need to understand how the device will be used. Then the purchased moisture meter will fully meet the necessary requirements.

Criterion #2 - Humidity Range

Optimal air humidity is determined by the purpose of the premises. In bedrooms and living rooms, normal moisture meter values ​​range from 20 to 80%. Near the balcony, in the hall, attic and in the kitchen from 10 to 90%. We recommend reading more about air humidity standards in an apartment in this material.

In moisture-filled rooms, the range of operating values ​​can reach 100%. The wider the range of values ​​captured by the device, the higher its price. Therefore, when choosing a gadget for bedrooms, halls and attic space, you can opt for devices with a small range of values.

When purchasing a hygrometer, study the performance characteristics specified in the product data sheet. It is important that the device parameters include the upper values ​​of the range of expected operating temperatures

For some moisture meters, the maximum heating threshold is important. Thus, a device for a bath or sauna should include in its operating temperature range values ​​up to 120 °C. Therefore, in rooms where temperature and humidity can reach quite high values, you should purchase special instruments for measuring vapors in the air.

Criterion #3 - measurement accuracy

For the equipment of special storage facilities, instruments with the smallest reading error are required.

So, in a home wine library, the humidity of the circulated air should be kept at 65-75%, and the content of water vapor in the library should not be lower than 50 and higher than 60%.

Therefore, to measure the moisture in the air in such rooms, you should use a psychrometer or a high-precision electronic hygrometer, which measures the amount of water vapor by changing the electrical conductivity of the air.

The error of a psychrometer ranges from 1 to 5%, the error of a digital device is from 5 to 10%. Therefore, they can be used in rooms where air humidity must adhere to precisely specified values.

If the humidity level does not meet the standards, but you need a device to increase it - humidifier.

Conclusions and useful video on the topic

The video will talk about the operating principles of stationary psychrometers and will compare the results obtained with the indicators of digital hygrometers:

Optimal air humidity in rooms reduces the risk of chronic diseases, alleviates the symptoms of existing bronchopulmonary diseases, and reduces the manifestation of allergic reactions.

The amount of moisture in the air affects a person’s performance, appearance and health. Therefore, measuring indoor water vapor should become a good habit in every family..

Do you still have questions about choosing a hygrometer? Or would you like to add useful comments to our publication? Write your comments under this material.

If you have a hygrometer at home and want to talk about its pros and cons, write about it below the article.