Hygrometers measure humidity in both indoor and outdoor environments, humidors, clean rooms and vessels built for land, sea and air. Temperature and humidity are key measurements for scientific, industrial and maintenance projects. The scientific processes used include simple mechanics, electrical capacitance and resistance, dew and frost condensation on chilled mirrors and mixtures of certain salts like magnesium chloride, potassium carbonate and lithium chloride.
Resistance changes in electricity conduction help to measure changes in ambient moisture. Electrical hygrometers use a semiconductor that is usually composed of a sheer layer of lithium chloride. Humidors and storage areas frequently use electrical hygrometers to monitor moisture. Chilled mirror technology, which is used in many scientific processes, often requires use of a microscope to provide direct observation of the phase states of moisture that collects on mirror surfaces.
Frost-point hygrometers use cryogen and heat to maintain a steady frost temperature. Advanced quasi-spherical resonators used in dew-point hygrometers detect onset of condensation with pinpoint accuracy. New scientific discoveries like laser-controlled hygrometers continually broaden the choices of hygrometer technology for homes, businesses, research and industry,
Determining the best hygrometer for your measuring purposes depends on how accurate you need your readings to be, whether you want to initiate automatic moisture corrections when humidity falls outside of preset boundaries and the span of temperatures of the gases being measured. You might only need a simple mechanical hygrometer or a multiple-stage dew-point sensor.
Psychrometry has been a popular method of measuring humidity for many years, but many people define hygrometers as only those devices that measure changes in materials. The earliest hygrometers used hair and tension to determine moisture changes. Of course, chilled mirror technologies measure dew points, frost points and isothermal changes. Most hygrometers use capacitance or electrical resistance combined with thermometers to measure humidity.
Scientifically, humidity affects everything in the environment including bacterial growth, corrosion, wear on building materials and personal comfort. Moisture affects how warm or cold people feel. For example, you could feel comfortable at 70 degrees with the right relative humidity, but remain cold at 80 degrees if the air is dry, which commonly occurs with some types of heating. Adjust your humidity by using a hygrometer, and you could save on heating and cooling bills by using simple science. The more humid the air, the less evaporative cooling occurs.