Hygrometers - Room Thermometers

Accuracy is a key factor to consider when purchasing a room hygrometer. For example, a high-accuracy room hygrometer would be necessary for a food safety inspector, as strict standards must be met regarding food storage and refrigeration. In contrast, if you are looking for an air humidity meter for use in your home, a device with lower accuracy would provide an adequate estimate of indoor relative humidity.

For temporary humidity measurement applications (such as simple control measurements, on-site checks to assess concrete drying conditions, or assessments of the performance of the heating, ventilation and air conditioning (HVAC) system), a portable air humidity meter without memory can be used.

For long-term or continuous monitoring of relative humidity, a fixed air humidity meter with memory and data logging capability is ideal. Many fixed air humidity meters with memory logging and storage record humidity measurement data with date and time either in internal memory or on a removable SD memory card. Depending on the model, some air humidity meters for continuous monitoring also record and store the minimum and maximum readings and/or emit an alarm when a specific air humidity threshold set by the user is reached. Most data-logging air humidity meters allow the transfer of stored data to a computer using dedicated software, a USB or RS-232 interface cable and/or an SD memory card reader. Transferring data to a computer facilitates documentation and reporting, as measurements do not need to be recorded manually. In addition, some air humidity meter products store data in a format compatible with Microsoft Excel. Fixed air humidity meters used for continuous monitoring of climate-controlled environments such as refrigerated trucks, storage units, warehouses and museum archives are used to inspect internal environmental conditions as part of safety and quality assurance. Air humidity meters with memory also help document an organization’s compliance with industry standards and best practices. Air humidity meters for permanent installation usually come with the necessary brackets or hardware required to mount the device on a wall or DIN rail. Often, a fixed-installation air humidity meter instrument is equipped with a mounting base or tripod so that the device can be positioned as required on a desk, table, counter, or workbench. If it is necessary to read humidity measurement results from a distance, you should choose an air humidity meter with a large, easy-to-read liquid crystal display (LCD). In addition, when working in low-light or dark environments, it is important that the display has backlighting.

Again, the application plays an important role when selecting an air humidity meter. For non-professional use, a simple air humidity meter is recommended that only needs to be switched on to start the measurement. Most professional uses require an air humidity meter with more advanced functions. Keep in mind that the more functions an air humidity meter has, the more complex it will be to use. However, experienced contractors, technicians and engineers will be more than comfortable using an air humidity meter with additional functionality, as the menu structures of digital air humidity meters are somewhat standardized across the testing, measurement and inspection equipment industry. If an air humidity meter has many different functions, it can be useful for the device to have multiple buttons or keys, as more keys can provide time-saving shortcuts for navigating a device’s menu structure.

The waterproofing protection of the air humidity meter (See IP Codes) is an additional factor you should investigate before purchase. Depending on the expected operating conditions, the air humidity meter may need to be made of durable material, such as high-quality ABS plastic. The housing of the air humidity meter may also need to be water-resistant or waterproof. Finally, do not forget to evaluate the power supply and accessories of the air humidity meter. If the air humidity meter is battery-powered, the batteries should be a commonly used size so they are easy to find and replace cost-effectively. If the air humidity meter is powered by an AC adapter, make sure that the power cable will not interfere with other aspects of your working environment.

In modern measurement technology, an air humidity meter is often used in combination with a temperature measuring instrument. The measured values for relative humidity and temperature can be used simultaneously to determine the dew point or the water vapor content.

Humidity, also called relative humidity or air humidity, is defined as the amount of water vapor in the air. However, humidity is relative. It is normal and in fact important for air to contain water vapor. The amount of water vapor in the air depends on many factors, including air temperature. Warm air is generally more humid than cold air. This means that when air temperature decreases, the maximum amount of water the air can hold also decreases. An air humidity meter displays readings as a percentage of relative humidity (% RH). Thus, if an air humidity meter displays a measurement result of 20% RH, then the air holds 20% of the maximum possible amount of water at that temperature. When the air is humid outdoors, water and sweat evaporate more slowly. Fog, dew and precipitation become more likely. Indoors, high humidity can cause symptoms for those who suffer from allergies, asthma and chronic obstructive pulmonary disease (COPD). Excessive condensation can also form in overly humid indoor environments, resulting in the growth of mold and bacteria. However, when indoor air is too dry, the skin becomes dry and may even crack. Some people also experience problems with nosebleeds in very dry climates. When the air is too humid indoors, sometimes it may be sufficient to simply open a few windows and doors. Other times, the performance of the HVAC system should be evaluated by a trained professional.

Application of humidity meters in warehouses and storage areas

The durability and service life of many materials depend on the climatic conditions in the warehouse. Excessively high air humidity as well as very low humidity can be harmful and cause damage to stored products. In order to protect high-quality and sensitive products, the temperature and humidity in the storage area should be monitored with a humidity measuring device and adjusted if necessary. If the specified limit values are exceeded, some humidity meters can trigger alarms or automatically activate devices for ventilation, temperature control, dehumidification or humidification. Before storage, it must be clarified which temperature and humidity requirements must be met for the specific materials to be stored.

If different materials with different requirements are to be stored, it is recommended to select and prepare separate storage areas according to the requirements. Food to be processed in canteen kitchens, for example, has very different requirements in terms of temperature and humidity. While flour, sugar, salt and nuts must be protected from excessive humidity, freshly harvested foods that have not been specially preserved, such as potatoes, vegetables, salads and certain types of fruit, require relatively high relative humidity. Since the fruits themselves contain a lot of water, they lose their taste and texture when moisture is released into very dry air.

Humidity meters are also important for monitoring the indoor climate in raw material and finished product warehouses in manufacturing companies, so that electronic components, paper, textiles and corrosion-resistant metal parts do not become unusable due to incorrect storage conditions

Good climate in offices

In many professions, people spend most of the day in the same room. The climate there is important for well-being and therefore for employee performance. Important factors for the indoor climate are temperature, humidity, air velocity and thermal radiation. Temperature and humidity can be checked with a simple humidity meter that also displays temperature.

However, the perception of temperature, as outdoors, is influenced by air velocity, air humidity and heat radiation. To assess room temperature, it is not sufficient to simply measure the air temperature. The temperature resulting from the air temperature and the mean radiant temperature of the surfaces enclosing the room is called the operative room temperature. It can be determined from the air temperature and the surface temperatures of walls and ceilings or with the help of a special thermometer, the globe thermometer or black globe thermometer. Air velocity and humidity also influence the regulation of body temperature through the skin and therefore the sensation of warmth. If the air temperature is lower than body temperature, higher flow rates lead to faster cooling of the body, which is usually desirable in hot weather. However, high humidity prevents regulation of body heat through sweating. For physiological reasons, values for maximum relative humidity are specified in the technical rules for workplaces ASR A3.6. The permissible value is 80% at an air temperature of 20 ° C, 70% at 22 ° C, 62% at 24 ° C and only 55% at an air temperature of 26 ° C. There are humidity meters for indoor climate measurements that are equipped with a sensor for measuring flow velocities and other special devices with functions for assessing thermal stress load. Also, high levels of carbon dioxide and pollutants in indoor air affect the ability to concentrate in the workplace and can lead to health problems. Values for carbon dioxide, formaldehyde and volatile organic compounds can be determined with inexpensive measuring devices. Many of these environmental measuring devices simplify the evaluation of measurement results by providing visual or audible signals that limit values have been exceeded. One can then reduce the pollutant content in the room air, for example, through targeted ventilation.