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Hygrometers are devices that measure air humidity. This model, displaying high humidity, also includes a thermometer. Image courtesy of Alex Tihonov/Getty Images.Water vapor is present in the air, and the humidity it creates can impact us. Our bodies sweat to cool off, but when the humidity is too high, sweat doesn't evaporate efficiently, leaving us with that uncomfortable sticky feeling. This causes the temperature to feel much warmer than it actually is when humidity levels are elevated.
On the other hand, low humidity makes sweat evaporate quickly due to evaporative cooling, which helps regulate body temperature. But how can you keep track of humidity in your surroundings? A hygrometer is the tool for the job. There are various types to suit different needs, all designed to measure humidity—a feature that regular thermometers simply can't provide.
The Evolution of Humidity Sensors
Hygrometers are devices designed to measure the moisture content in the air, which refers to the amount of water vapor present. Many of these instruments also measure temperature, as it plays a vital role in calculating humidity levels.
Hygrometers were first introduced in the 15th century, taking on various forms. One early contributor, Leonardo da Vinci, created a model that measured the difference between absorbent and nonabsorbent materials. This difference, caused by moisture absorption from the air, served as a method for measuring relative humidity.
Another significant early design came from Swiss physicist and geologist Horace Bénédict de Saussure in 1783. His instrument gauged the effect of atmospheric moisture on the tension of a strand of human hair, which helped determine humidity levels in the air. From these early designs, modern technology now allows us to measure humidity in a localized region using reliable electronic devices.
The Many Benefits of Measuring Humidity
Nowadays, hygrometers have a wide range of applications. As with many scientific instruments, there are budget-friendly options available for casual use. However, if you're seeking high-end models used by meteorologists, expect both accuracy and price to rise significantly. Hygrometers play key roles in the following fields:
- weather prediction
- construction and industrial manufacturing
- moisture regulation in homes
- plant care in greenhouses
- controlling humidity in saunas for residential and commercial use
- preserving delicate materials (artwork, artifacts, documents, musical instruments) in museums and archive buildings
Exploring Wet and Dry Bulb Temperature
When it comes to determining humidity, two key terms are often mentioned: wet bulb temperature and dry bulb temperature. Dry bulb temperature is what you would read on a standard thermometer, and it doesn't account for moisture content in the air.
Wet bulb temperature, on the other hand, gets its name from the method used to measure it. A thermometer wrapped in a wet cloth is exposed to air, and it measures the rate at which water evaporates. This rate helps to calculate both moisture content and relative humidity.
Different Types of Hygrometers
There are several types of hygrometers available, including:
- Mechanical hygrometer: Determines humidity by observing the expansion and contraction of organic materials.
- Electrical hygrometers: Detect changes in the electrical resistance of conductive materials, and come in two types: resistive (measuring contraction in ceramic material due to humidity) and capacitive (measuring the electrical flow between two metal plates influenced by moisture).
- Dew point temperature hygrometers: Known for precision, they gauge the condensation on a cooled metal surface.
- Psychrometer: Compares the readings of a dry bulb thermometer and a wet bulb thermometer to estimate humidity.
Certain hygrometers use capacitive sensors, while others utilize resistive sensors. Both types measure relative humidity, but they differ in how they operate. Capacitive hygrometers detect moisture by changes in electrical capacitance, while resistive hygrometers rely on electrical resistance to determine the dew point.
Advantages of Hygrometers
Hygrometers are also valuable tools for personal health. Dry air can lead to discomfort, while air with excessive moisture can promote the growth of mold and pathogens. Affordable hygrometers can help you monitor the humidity levels in your home, office, or workspace, improving air quality and preventing mold formation.
If your home experiences creaky wooden furniture, a build-up of dust, and static electricity—especially when touching door handles or light switches—it’s likely that the humidity is too low. On the other hand, if humidity levels are too high, mold growth and condensation on windowsills may occur. A reliable hygrometer can help you regulate humidity and detect condensation.
To measure the humidity in your home, simply place your hygrometer in a living area, away from the kitchen and bathrooms. ThermoPro, a known hygrometer manufacturer, recommends maintaining the absolute humidity in the home between 40 and 50 percent. If the humidity is too low, you can try using room humidifiers or a whole-house humidifier as part of your HVAC system. Dehumidifiers can help reduce excessive moisture levels.
If you experience dry skin, cracked lips, or chafed skin in the winter, or wake up with a sore throat every morning, the humidity in your home is probably too low. Even if you invest in skincare products, taking simple steps to improve the humidity in your living spaces can make a significant difference.
