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Hygrometers are precise scientific instruments used to measure humidity, also referred to as psychrometers and humidity sensors. Note that hygrometers measure relative humidity (%), which is the amount of vapor in the air compared to the highest possible amount. Absolute humidity, on the other hand, is the amount of vapor in a certain unit volume of air at a given temperature (e.g., g/m3).
Measuring humidity or water vapor in the air, soil, and confined space is essential. Inappropriate humidity levels in buildings, for example, can lead to poor environmental health and storage conditions. In fact, high humidity levels may lead to home pollutants, mold, and viruses, while low levels may cause skin irritation, electrostatic discharge, and breathing problems. Hygrometers are also used in industrial settings, manufacturing, greenhouses, museums, wine cellars, and cigar warehouses.
Types of Hygrometers
Hygrometers can be employed in a variety of settings, such as education, manufacturing, medical settings, and research. Thus, it’s no surprise that such instruments come in all shapes and sizes. Interestingly, the design of hygrometers has evolved significantly over the years. Note that it was in the 15th century when Leonardo da Vinci invented the first hygrometer.
While the majority of modern hygrometers use a material that attracts moisture and changes depending on how hydrated it is, there are different types of humidity measuring devices. Weather houses, for example, are old twisted-fiber hygrometers in which two figurines mounted on a turntable take turns coming out of a door, depending on how wet or dry the air is. Other mechanical hygrometers also use fiber material, such as human hair. To measure the amount of moisture, however, more advanced units are needed. The psychrometer, for example, consists of a pair of thermometers (with a wet and a dry bulb, respectively); depending on the evaporation and the temperature difference between the meters, one can measure the relative humidity in the air. Electronic hygrometers, on the other hand, facilitate readings; they can measure either capacitance or resistance and calculate humidity. Note that capacitive units consist of two metal plates and assess the ability of these plates to store a static electric charge, whereas resistive meters measure the electric current flow through ceramic material exposed to the air. There are also dew point hygrometers that are extremely precise; they consist of a metal surface and measure the moisture that condenses on it. Last but not least, there are hygrometer apps for smartphones (with built-in humidity sensors) or standalone sensors (with USB or wireless connectivity).
Buying a Hygrometer: Factors to Consider
As there’s a wide variety of units for sale, choosing a hygrometer can be a daunting task. Prospective buyers should consider three major factors: requirements, specifications, and costs.
Requirements: First of all, users should decide where they’ll be using their hygrometer (home use, industrial settings). While hygrometers for home use do not have to be 100% accurate, buyers should consider if humidity will be measured in multiple rooms simultaneously or hard-to-reach areas (e.g., attic). If one wants to measure humidity outside, a home weather station is recommended instead.
Specifications: When buying a hygrometer, users should understand that accuracy is critical. When it comes to digital units, +/- RH ratings should be considered. Factors such as power source, user interface, data logging, and access to historical data are also important. As mentioned above, if one wants to monitor several places simultaneously, a hygrometer that can connect to different sensors as one system is needed. Last but not least, updates and alerts that allow users to monitor humidity remotely are also beneficial.
Total costs: When it comes to meters, more precise instruments are often more costly. Note that humidity measurers designed for industrial use may need additional NIST Traceable certification.
Best Hygrometers for Sale
Hygrometers are excellent scientific instruments. Given that hygrometers have a wide variety of applications, it’s no surprise there are a plethora of units for sale. Unfortunately, buying a hygrometer can be a challenging task. Based on different parameters and user reviews, here are the best humidity meters for sale. Note that thermo-hygrometers are a popular alternative.
- ThermoPro TP55 Digital Hygrometer – Indoor Thermometer, Humidity Gauge with Jumbo Touchscreen, and Backlight Temperature Humidity Monitor
ThermoPro TP55 Digital Hygrometer – Indoor Thermometer, Humidity Gauge with Jumbo Touchscreen, and Backlight Temperature Humidity Monitor is one of the most precise units on the market. Note that this product has both humidity and temperature sensors. The unit is equipped with professional-grade sensors and has high accuracy (2-3% RH and +/-1°F/°C), with readings that update every ten seconds. This meter also provides humidity trends and records (24 hours/all-time/high and low records) and shows temperature changes in both °F and °C. With its large touchscreen display with a backlight (that turns off after 15 seconds), this unit is an attractive humidity meter.
- AcuRite 01083 Indoor Thermometer & Hygrometer with Humidity Gauge & Pro Accuracy Calibration
AcuRite 01083 Indoor Thermometer & Hygrometer with Humidity Gauge & Pro Accuracy Calibration is another great unit with strong magnetic backing. This meter measures both relative humidity from 1-99% (low/high/okay) and temperature (in °F and °C). It also ensures fast data reporting to create a comfortable living environment and better air quality (with updates every 10 seconds). Moreover, this temperature sensor and humidity gauge have an easy-to-read digital display, which makes it an attractive gift choice for both professionals and beginners.
- AcuRite 01080M Pro Accuracy Temperature and Humidity Gauge with Alarms
AcuRite 01080M Pro Accuracy Temperature and Humidity Gauge with Alarms is a power meter that can measure indoor humidity (1-99%) and temperature (from -4 to 158°F or from -20 to 70°C). Note that it provides an accuracy of +/-0.5°F and +/-2% (with manual calibration options). The unit shows updates and records, including alarm notifications, to indicate when the humidity and temperature levels are outside of one’s ideal range. Note that less than 25% means a dry environment, 25-55% indicates a comfortable environment, and over 55% shows humid settings. Last but not least, this meter is compact and versatile (tabletop, wall-mountable, and magnetic back mount) – simply one of the best hygrometers for sale.
- RockyMars RT36 Temperature and Humidity Meter
RockyMars RT36 Temperature and Humidity Meter is another great unit available on the market. The model is light and compact, which makes it a great portable hygrometer. Note that it uses three AAA batteries. It can also measure temperature from -10°C to 60°C or 14°F to 140°F, with an accuracy of +/-1.0°C or +/-2.0°F. This meter is ideal for facility maintenance, environmental monitoring, HVAC, and health care. Besides, it comes with a manual to ensure accuracy and a positive user experience.
- ThermoPro TP65A – Indoor/Outdoor Thermometer, Digital Wireless Hygrometer, Temperature and Humidity Monitor with Jumbo Backlight Touchscreen and Cold-Resistant Outdoor Thermometers (200ft/60m Range)
ThermoPro TP65A – Indoor/Outdoor Thermometer, Digital Wireless Hygrometer, Temperature, and Humidity Monitor with Jumbo Backlight Touchscreen and Cold-Resistant Outdoor Thermometers (200ft/60m Range) provides users accurate humidity and temperature readings for both indoor and outdoor settings. Note that the unit can be connected to three outdoor remote sensors to assess different locations and has a waterproof outdoor thermometer sensor, which is efficient in rain or snow (as cold as -31°F/-35°C). Additionally, the unit’s indoor/outdoor wireless thermometer has a range of 200ft/60m and is capable of strong signal penetration (433 MHz). With its large display and advanced settings, this meter is ideal for a variety of applications.
- Temp Stick Wireless Remote Temperature & Humidity Sensor
Temp Stick Wireless Remote Temperature & Humidity Sensor is a sophisticated remote temperature and humidity monitor that uses two AA batteries (included). The unit allows users to check humidity (0-100%) and temperature (-40°F-140°F) levels in buildings, fridges, and hard-to-reach areas remotely. The unit supports data logging with unlimited history and sends text and email alerts to indicate an important change in temperature or humidity (note that it can alert multiple users). Moreover, the phone app and computer webpage are easy to use.
- SensorPush Wireless Thermometer/Hygrometer for iPhone/Android – Humidity & Temperature Smart Sensor with Alerts
SensorPush Wireless Thermometer/Hygrometer for iPhone/Android – Humidity & Temperature Smart Sensor with Alerts provides reliable measurements via Swiss-made sensing components. The unit has -40°C-60°C (-40°F-140°F) temperature and 0-100% humidity ranges. Note that this meter is a powerful model (with a range of 325 feet), which makes it ideal for tracking humidity in hard-to-reach areas, such as guitar cases, attics, and basements. Besides, the app is easy to navigate and provides unlimited in-app data storage (compatible with iOS 8+, Android 5.0+, and Bluetooth 4.0+/LE).
- Ambient Weather WS-3000-X5 Wireless Thermo-Hygrometer with Logging, Graphing, Alarming, Radio Controlled Clock with 5 Remote Sensors
Ambient Weather WS-3000-X5 Wireless Thermo-Hygrometer with Logging, Graphing, Alarming, Radio Controlled Clock with 5 Remote Sensors is an advanced thermo-hygrometer with wonderful interface settings. The unit has a TFT color display that allows the graphing and monitoring of various parameters, such as temperature, humidity, dew point, and heat index (note that it allows users to monitor up to eight channels at the same time). The clock included automatically synchronizes the time several times a day and adjusts for daylight savings (it includes 24 time zones throughout the world). The unit also allows users to set high and low alarms (both audible and visual) for any of the measured parameters. Last but not least, this meter includes PC software for advanced data analysis, console programming, and easy data extraction from the optional micro-SD card.
- Extech Digit Thermometer
Extech Digit Thermometer is a great unit that displays relative humidity, temperature, and dew point. Note that this model recalls minimum and maximum readings and provides visual and audible warnings. Additionally, the meter has a remote probe that can extend on an 18-inch cable, which makes it ideal for measurements behind walls and hard-to-reach areas. Additional NIST Traceable certification is available, allowing the monitoring of environmental conditions in laboratories, storage areas, and manufacturing assembly places.
- Cigar Oasis Analog Hygrometer by Western Humidor
Cigar Oasis Analog Hygrometer by Western Humidor is a precise analog hygrometer. Note that the unit’s humidity sensor has an accuracy of +/-1%. Besides, the unit is user recalibrate-able. With a scratch and fog-resistant glass face, an aluminum case, and a secure magnetic mount, this hygrometer is highly valuable, particularly in the cigar industry.
Hygrometers are invaluable instruments in numerous settings. They are ideal for weather monitoring, home use, automated manufacturing processes, monitoring environments in museums and training centers, plant nurseries, and product research. Note that some popular industrial applications include polyethylene production, liquefaction of natural gas, medical equipment, food packaging, coatings industry, and incubators. Small and portable devices are ideal for field work, while decorative models are perfect for home use.
Portable, freestanding, wall, and magnetic units all need proper calibration, maintenance, and storage conditions to ensure accurate and long use. To provide an example, users should realize that exposure to high relative humidity may create an offset in readings. Calibration and period re-calibration are also essential to guarantee accurate measurements and readings.
Hygrometers are invaluable scientific instruments used in a variety of applications to measure humidity levels. Measuring humidity levels in the air, soil, and enclosed space is essential to guarantee positive health outcomes and comfort, proper storage conditions, and effective manufacturing processes. Given their diverse applications, it’s no surprise hygrometers designed for home uses are increasing in popularity. Note that some units measure humidity in a single spot, while others come with different sensors to facilitate monitoring in various areas.
Here we should note that although hygrometers come in different shapes and sizes, digital hygrometers and apps are preferred as they provide automatic readings, updates, and alerts to help users track humidity. That being said, prospective buyers should consider three major factors: requirements, specifications, and total costs. Accuracy, data logging, history records, and design are major factors to consider. Units that measure both humidity and temperature are also highly popular.