Hygrometer – What Does It Measure

Hygrometer definition: hygrometers are weather instruments used to measure the level of humidity in the air also known as “relative humidity” or RH.

Basically, there are 3 primary kinds of hygrometers. Digital, mechanical, and wet and dry bulb.

Hygrometer – What Does It Measure

What to Know about Humidity

Humidity is the water vapor in the atmosphere that is caused by evaporation and condensation. It may be measured as absolute humidity or relative humidity.

Absolute humidity is actually the water vapor in the air’s unit volume while relative humidity(RH) means the moisture’s ratio in the atmosphere to maximum moisture that atmosphere could hold.

It’s what provides you uncomfortable sticky feeling on hot days and may cause heat stroke. People feel most comfortable with an indoor RH between 30% and 50%.

How Humidity Affects You?

Humidity is crucial for one’s health and comfort. It has been linked to a lack of observation, irritability, low observation skills, lethargy, and sleepiness.

Also, it plays a factor in heat exhaustion and heat stroke. Aside from affecting people, too little or too much humidity could affect your personal belongings.

Low humidity could dry out and leave damages to your furniture. On the contrary, a high amount of humidity can cause moisture stains, mold, swelling, and condensation.

Hygrometers – How Do They Work?

Basically, a wet and dry bulb psychrometer is the most common and simple way to measure humidity.

This kind of hygrometer uses 2 basic mercury thermometers, one with a dry bulb and the other is with a wet bulb.

Evaporation from water on wet bulb causes its temperature reading to reduce, which causes it to show low temperature than dry bulb.

RH or relative humidity is actually calculated by comparing the readings with the use of a calculation table, which compares ambient temperature.

This is the temperature provided by the dry bulb to the difference in the temperatures between 2 thermometers.

The mechanical hygrometers use slightly more complicated systems based on a first hygrometer made in 1783.

The system uses organic materials, typically human hair, which contracts and expands as a result of surrounding humidity.

It also explains why you seem to have a bad hair day when it is humid and hot.

Organic materials are held under slight tensions by springs, which are linked to the needle gauge, which indicates the humidity level based on how hair moved.

How to Measure Humidity

Before you can figure out the ways to measure something, you need to have a clue of what you are measuring and what measurements would mean.

You can measure most things in a scientific unit of a kind or another including seconds, meters or kilograms.

However, humidity is different and you can measure it in 2 various ways.

A possible measurement is known as the specific humidity. It’s basically the mass of water vapor that is present in a kilogram of air mass like water, written in units like grams per kilogram.

There is a similar measurement to this and it is known as mixing ration.

This is the water vapor’s mass in dry air’s kilogram mass, which is written in units like grams per kilogram.

The relative humidity is a more common measurement. It’s the water vapor in the air in comparison to the maximum amount there could be at the temperature written as a percentage without any units.

On a soggy and wet day, the relative humidity is 90-100%. On a dry day with the dry wind blowing and no or little chance of rain, it’s more likely to be 60% to 75%.

Once you talk about humidity as a percentage, it means relative humidity.

Since particular humidities are meaningless to many people, weather forecasts usually quote relative humidity and a user-friendly hygrometer is calibrated.

It can be marked with measurements on their displays or dials.

Who Can Benefit from Hygrometer?

Many people asked questions like: Who uses hygrometers? Who can benefit from using it? Well, hygrometers can be complex and big or even small.

It can be included in handheld devices that measure some key atmospheric conditions.

Currently, they are used by several professionals and industries like the ones who are involved in weather forecasting and professionals who need to maintain humidity in residential areas and museums.

HVAC experts and people who participate in outdoor training and outdoor sports also use hygrometers.

Handheld and small devices that include hygrometers among some instruments can give accurate and fast readings of relative humidity and some essential atmospheric readings.

Such electronically powered devices may measure humidity through using materials, which have electrical resistance.

This resistance changes based on the amount of moisture absorbed.

True to the definition of hygrometers, the 2 commonly used sensors for the hygrometers are known as resistive and capacitive.

The resistive sensors use membranes made from the polymers. This kind of sensor registers the changes in conductivity if the water is absorbed.

The capacitive sensors work through measuring the changes in how much water there is in the air by using electrical signals between 2 plates.

How to Get the Best Results from Using Hygrometers

Hygrometers should be calibrated at least once a year to make sure that they provide accurate results possible.

Even the most expensive and best hygrometer’s accuracy will alter in the long run. Place your hygrometers in the sealed container alongside a glass of salt water to calibrate.

Place this in the room where the temperature stays constant relatively throughout the day. After that, leave that to sit for ten hours.

Once 10 hours end, hygrometers must display an RH level of 75%. If not, you must adjust the display.

What Types of Hygrometers Should You Use?

Well, the answer to this question depends on some factors. It means that before you shop around for a hygrometer, make sure to know needs first.

In this way, you will know what kind of hygrometer to use.

Your budget also plays a huge role. Although hygrometers are not really expensive, you can find a model that suits best to your budget.

In my opinion, the best is to have a digital hygrometer in your crawl space, your house, your garage or other places you want to measure the humidity. You don’t need to stress out with calibration and mechanic hygrometers

If you have decided on the best hygrometer to use, you can purchase the ones with features that will be more helpful and beneficial to you.