At WiseGEEK, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.
A digital thermo-hygrometer is an electronic instrument that can measure and display the current temperature and relative humidity. It is small enough to be portable or hand-held, and it typically uses batteries for power. The components measure temperature and humidity with changes in electrical resistance, and it continuously displays the measurements on the screen of the unit. Some models are made to help forecast the weather and might include additional features, while others are manufactured for auxiliary purposes such as aiding mold remediation.
In most cases, a digital thermo-hygrometer will have a metal or plastic body with a liquid crystal display (LCD) screen that displays the measurements. The current temperature is measured by changes in electrical resistance due to heat, and it might be shown in either degrees Fahrenheit or Celsius. Relative humidity, which is the percentage that the air is saturated with water vapor, is calculated with changes in electrical resistance caused by changes in moisture. The digital thermo-hygrometer continuously updates and displays the numerical measurements on the screen when it is turned on.
Some types of a digital thermo-hygrometer come with a wireless sensor that can be placed in a different location from the main unit. The remote sensor measures the temperature and relative humidity in that location and transmits it to the main unit. The screen on the unit can then show the measurements from both the location where the main unit is and where the remote sensor is placed. For example, this allows one to see the indoor and outdoor temperature and humidity at the same time. It might also measure additional weather characteristics such as dew point, wind chill, and barometric pressure.
One thing that a digital thermo-hygrometer can do is show the current weather. The temperature helps one to know how hot or cold it is, and rapid temperature changes can indicate a warm or cold front coming through. Warm air has the ability to hold more water vapor than cool air temperatures. During the summer, high humidity makes the air feel warmer than it actually is because the air becomes too saturated to allow sweat on the skin to evaporate and cool a person. On the other hand, in the winter, low humidity tends to make the air feel warmer than the current temperature.
A digital thermo-hygrometer can have other uses as well. It is often used in greenhouses to monitor the temperatures and humidity levels, and it can be used during mold remediation and home inspections to check air quality. Further applications include environmental studies, food distribution, and installation of heating and cooling systems in a building.