4 Ways to Measure Indoor Humidity

There are four ways to measure indoor humidity in a home, and we will dive into each method so that you can decide which one works best for you.

4 Ways to Measure Indoor Humidity In a Home:

  • Hygrometer
  • Wet And Dry Bulb Temperature Test
  • Ice Cube Method
  • Homemade Hair Hygrometer

If humidity is a concern for you, there are things you can do to get it under control. The first step is knowing what the humidity level in your home actually is.

Measuring Humidity In Home

What Is A Hygrometer?

A hygrometer measures the excess moisture levels in the air within a particular room. You may be experiencing air in your home that is either too damp or too dry. Hygrometers have been around for hundreds of years to measure indoor humidity, and today’s hygrometers can be very accurate.

Are Digital Hygrometers Accurate?

Digital hygrometers use modern technology and provide a more accurate reading. The majority of digital hygrometers give a reading for both humidity and temperature, and many keep track of temperature and humidity variations over extended periods of time. A watch battery is required for digital versions.

What Is an Analog Hygrometer?

An analog hygrometer detects humidity levels using wound-up springs and other intricate parts. Analog hygrometers require being recalibrated on a regular basis, as the longer the analog hygrometer goes without being reset, the less accurate its humidity level readings are.

There are those who prefer the look of an old, analog hygrometer and choose to use them over more modern, digital hygrometers.

Are Analog Hygrometers Accurate?

Analog hygrometers are accurate approximately 90% of the time, and recalibrating an analog hygrometer regularly is strongly recommended. To some, analog hygrometers have a visual appeal, so having a digital hygrometer as a backup to periodically double-check the accuracy may be beneficial.

How to Test Humidity without a Hygrometer

Humidity can be tested without a hygrometer using alternative methods yet are not as accurate. The wet and dry bulb temperature test can be performed providing one is able to find bulb thermometers that are actually no longer sold. The ice cube test and hair hygrometer test may also be performed.

Although there are other ways to check humidity levels, they are not as accurate as a hygrometer designed for measuring relative humidity.

Let’s take a look at your options.

Ice Cube Method

Although this method will indicate whether there is humidity in the room you wish to test, it will not be able to measure the humidity levels.

What You Need

  • Glass of water
  • 4 or 5 Ice cubes

Step 1: Select Which Room Will be Tested for Humidity

Decide which room you wish to test for your ice cube humidity test.

Step 2: Place the Ice Cubes Into the Glass of Water

This step is pretty self-explanatory.

Step 3: Place the Ice Water in the Room

Place the ice water on a desk, dresser, or table in the room you are testing. Let stand for about 5 to 10 minutes.

Step 4: Check for Condensation

Do you see condensation on the outside of the glass of ice water? If so, then you have a relatively high humidity level in the room that was tested.

When there is too much moisture in the air, the moisture will be drawn to the cold surface of the glass.

If you do not see condensation building up on the outside of the glass, this means the relative humidity in the room is very low.

Homemade Hair Hygrometer

Hair can be used to test if there is humidity in a home. In dry climates, hair will contract, and in climates with more moisture in the air, the hair will expand.

The very involved directions for the hair method of testing humidity can be found by visiting Science Buddies.

Wet And Dry Bulb Temperature Test

Important to note is that unless you have a couple of old mercury bulb thermometers, you will be unable to buy them. Mercury bulb thermometers have been phased out for home use, as mercury is toxic to humans.

The wet and dry bulb temperature method is quite simple, so if you have a couple of them laying around, you’re in luck. Just be careful not to break them, as again, the mercury is toxic and not your friend.

What You Need

  • Two standard bulb thermometers
  • A moist piece of cloth
  • A fan

Step 1. Select the Room You Wish to Test

Decide which room you wish to test the humidity level in.

Step 2. Get a Fan

You will need a fan for this test, so find one and bring it into the room with you. You’ll want to have the fan facing the direction of where you will have your bulb thermometers placed.

Step 3. Shake the Thermometer Bulbs

Shake each thermometer bulb so that the mercury collects at the bulb area of the thermometer.

Step 4. Wet a Small Piece of Cloth

Tape a small, wet (not dripping) piece of cloth around one of the bulb thermometers. The other thermometer will stay dry. Room temperature water is best to not change the temperature of the thermometer.

A cotton ball may also be used in place of a small piece of cloth. Either way, make sure whatever you choose is damp yet not dripping wet, and tape it to the thermometer.

Step 5. Place the Thermometers in the Room

Place both thermometers in the room to be tested, directly in front of the circulating fan. Allow the fan to run on the bulb thermometers for five minutes.

Step 6. Check the Temperature of Each Thermometer

Check the temperature of each thermometer and write down what you see. Subtract the wet bulb temperature from the dry bulb temperature.

Step 7: Check the Chart

After doing the math and subtracting the wet bulb temperature from the dry bulb temperature, use this chart to help determine the relative humidity in the room you just tested.