Ways To Measure Humidity Without A Hygrometer

Humidifiers are essential devices to have in your home, especially when there is dry air. Humidifiers offer several benefits such as reducing allergy symptoms, fighting off dry skin, keeping germs away, and much more. Low humidity can be a serious issue when the amount of water vapor in the air is too low. However, there may come a point where your humidifier causes problems, as humidifiers can be overused.



If you have a humidifier that’s constantly running at home, you may be putting your home and your family at risk for complications. For example, when you overuse your humidifier, you can make allergy symptoms worse. Excess humid air can also increase the ability of airborne pathogens, like bacteria and viruses, to spread around your home. Furthermore, environments with high humidity levels are perfect for mold and mildew to grow, which can have negative consequences on your health. You may even be in need of a dehumidifier.

What’s more, as humidity levels increase in your home, the structure of your home may be at risk. As mold begins to grow on walls, ceilings, or other surfaces, it degrades the surface. When mold becomes established somewhere and spreads sufficiently, that surface needs to be replaced. That means you may have to completely remove sections of your ceiling or wall due to excess moisture.

However, if you check your humidity levels, you may notice your home is too humid. You can then act quickly enough to reduce the likelihood of mold growing somewhere.  

To make sure you’re not putting your home or family at risk, you need to be able to measure the humidity levels in your home. Typically, you would measure absolute humidity with a tool known as a hygrometer. 

If you don’t have a hygrometer, there are still other creative ways to get a humidity reading. While you can’t expect to receive a 100% completely accurate reading, you’ll get a good idea of if it’s too humid or not.

What Is A Hygrometer?

 Humidity and Hygrometer

At the most basic level, a hygrometer is a tool that’s used to measure humidity levels. It does so by measuring the amount of water that’s present in the atmosphere. How you take the humidity measurement depends on the type of hygrometer you use, as there are several types.

The most common type is an electrical hygrometer. In the electrical hygrometer group, you can find devices that measure humidity based on resistance or capacitance with electronic sensors.

A device that measures capacitance does so by utilizing two metal plates with space between them. In this open-air space, the device measures the amount of moisture in the air as it changes the static electric charge between the two plates.

The other type, a resistive electrical hygrometer, uses an electrical current passed through a ceramic material to test moisture in the air. As the ceramic component comes into contact with air that has some level of moisture in it, the electrical current is changed due to the resistance provided by water. Thus, the resistance recorded correlates to the amount of moisture in the air.

While measuring humidity with one of these electrical devices is quick and easy, you shouldn’t skip out on checking the humidity levels without one.

Wet And Dry Bulb Temperature Test

One of the easiest and most efficient ways to make a homemade hygrometer is known as the wet and dry bulb test. The method is named after the use of a wet-bulb and dry-bulb thermometer and the temperatures they produce. 

A dry-bulb thermometer is just a standard thermometer. On the other hand, a wet-bulb thermometer is a standard thermometer that uses a wet or moist piece of cloth that is wrapped around the bottom, or the bulb, of the thermometer.  

Thus, the dry-bulb temperature is the standard air temperature. The wet-bulb temperature is known as the adiabatic saturation temperature. In other words, it’s the temperature that water evaporates into the air. In our case, the temperature corresponds to the temperature that water evaporates off our wet-bulb.

Now that those terms are out of the way, to use this method, you have to choose a room where you want to test the humidity. If there is no fan in the room, bring one in and set it up to point at a spot where you’ll palace the thermometers later.

Once you have your fan ready, you need to have two standard, mercury thermometers. Once you have them, shake them well until all the mercury has moved into the bulbs of each thermometer.

One of the thermometers is fine as is—you don’t need to do anything to it! For the wet bulb, you’ll need to get a piece of cloth, a cotton ball, or something similar. Get the cotton ball damp, but not dripping wet, and tape it to the bulb of one of the thermometers to act as your wet-bulb thermometer. It’s best to use room temperature water for this, so you don’t immediately change the reading on the thermometer.

With your thermometers ready to go, take them into the room being tested, and place them somewhere that you can feel the air blowing on the bulbs. Leave the fan running on the bulbs for around five minutes, after which, you can check the temperature difference on each thermometer after evaporation of the water droplets has taken place.

Write the temperatures down, and subtract the wet-bulb temperature from the wet-bulb temperature. From there, refer to this table or graph to use the difference in temperatures and the dry bulb temperature to find the relative indoor humidity.  

For example, if your dry-bulb measured 68 degrees Fahrenheit, and your wet-bulb measured 58 degrees Fahrenheit, the chart shows the relative humidity is 55%.

Ice Cube Method

The ice cube method is significantly different from the wet and dry-bulb test. This is more of an indication of the humidity in the room. You won’t be able to find a measurement of the relative percent humidity. However, it’s still effective if you want to know if it’s too humid or too dry.

All you need to do is take a glass of water and place four or five ice cubes in it. Take that glass of water and set it on a table in the room where you want to check the humidity level. Take five to ten minutes to let the magic work!

Once the time has passed, check the glass. If there’s condensation on the outside of the glass. That means the room has a relatively high humidity level. On the other hand, if the humidity level is too low, there will not be any condensation on the glass, so you can see big fluctuations.

If you’ve found there to be a lot of condensation on the glass, that means there’s too much moisture in the air, and it coalesced onto a cold surface. In this case, it may be best to try the wet and dry bulb test to get a more accurate reading. Alternatively, consider buying a hygrometer if you’re worried about the humidity levels.  

Homemade Hair Hygrometer

girl combing her hair

The last test on the list uses some creativity by utilizing human biology—hair! Hair naturally expands when it contacts moisture. However, when you’re in a dry climate, your hair will contract slightly. Thus, you can use a piece of your hair to test if there’s moisture in the air!

This method is straightforward and simple, but you’ll need a few more things compared to the ice cube method.

First, take a piece of paper out, draw an arrow on it, and cut it out. Make a hole in the bottom of the arrow that’s big enough to fit a pin in it while still retaining space so the arrow can rotate around the pin. Place the arrow on a piece of cardboard with a pin through the hole, keeping it in place.

Next, take a hair and wrap one end around the arrow, and the other in around a pin or a thumbtack that rests well above the arrow. The top pin where the hair is secured should make a right angle where the hair is wrapped around the arrow. The longer the hair, the better.

Now, you have your device ready. Take a blow dryer and blow it on the hair for a minute or two. You’ll see the hair retract a bit, and pull the arrow up. This is the 0% humidity mark. Next, spray a little bit of water on the hair so it becomes moist. 

The hair will expand as it absorbs as much water as possible. The hair will expand and let the arrow drop down a little. This is your 100% humidity mark.

At this point, you’re completely ready to test. You have your markers and your device. Now let your creation sit for half an hour to an hour to get a good indication of the humidity level in the air. Judge the percentage of humidity based on where the arrow points between your initial two marks.

The Bottom Line

In any home, it’s a great idea to have a humidifier. They offer several health benefits in addition to being comforting! However, you can’t let your home get too humid. By using one of the three methods above, you can test the relative humidity level in your home. Then you’ll be able to know if you need your humidifier on or off.  





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