how can i measure relative humidity in a room

How can I measure relative humidity in a room? Knowing your home’s humidity levels can help you make decisions for improvements.

Most people think they only need a humidifier to improve the air quality, but you should first learn exactly what the levels of humidity are.

And that makes people ask how to measure relative humidity in a room. Turns out, it is not all that tricky, after all!

You can measure the relative humidity in your room using a simple device called a hygrometer but be sure to learn about factors resulting in inaccurate readings. 

Know the Importance of Measuring Relative Humidity

importance of measuring relative humidity

The amount of moisture or water vapor in the air as a percentage of the highest amount the air could contain at that temperature is referred to as relative humidity (RH).

There are many compelling arguments in favor of taking a room’s relative humidity reading.

For instance: 


Keeping the temperature in our homes at a healthy level is crucial to our health.

A lot of what makes an indoor environment pleasant or unpleasant is the relative humidity.

With humidity levels being too low, you may develop issues like:

  • Skin irritation
  • Nosebleeds
  • Coughing
  • Breathing difficulties

Yet, high humidity can make the air seem heavy and sticky, leading to discomfort and even harmful mold growth.

Therefore, we have to maintain a healthy and pleasant indoor climate by monitoring relative humidity and making necessary adjustments.

Fact: If you measure the relative humidity of a room, you can pinpoint the hotspots where condensation and mold thrive so you can take preventative measures. 

Energy Efficiency

energy efficient

Keeping the humidity under control is another way to save money and energy.

Air conditioning systems use more energy to remove moisture from the air when the humidity goes up.

By monitoring relative humidity and keeping it at the right levels, we can lessen the strain on cooling systems and increase their performance. 


Buildings and materials like paper, wood, and textiles can all be negatively impacted by excessive humidity.

For instance, high humidity can lead to:

  • The curling of books
  • The warping of wooden floors
  • The growth of mold on fabrics

Rooms with such materials benefit from monitoring their relative humidity so that the right levels may be maintained to prevent harm. 

Lab Testing

humidity control

Humidity control is essential for product quality in the pharmaceutical, electrical, and food processing sectors.

The proper conditions must be maintained in labs and other testing facilities to minimize moisture-related damage and assure consistent quality, hence measuring relative humidity is crucial.

Fact: Humidity levels in the 30–40% range are ideal for the winter, as condensation on windows is a common problem in the winter due to the increased humidity. 

How Can I Measure Relative Humidity in a Room?

measuring relative humidity

With the right device, measuring relative humidity in your room does not have to be that difficult.

And in most cases, all you have to do is place a hygrometer in your room to measure how moist the air is in your room 

A Simple Option to Try

Before you go and buy a hygrometer, you can also get an idea about relative humidity in your room using “the Ice Cube Method.”

A glass of water and several ice cubes will do the trick. To begin, fill the glass with ice (two or three cubes should do it) and wait. Then check it again in four minutes.

If condensation forms or drips down the glass, the humidity is on the higher side.

Condensation indicates that the relative humidity is too high; if none forms, the humidity is likely to be a bit too low.

It is not a good idea to perform this test in your kitchen, as odors and steam from cooking could skew the results.   

Using a Hygrometer to Measure Relative Humidity in a Room

hygrometer measuring relative humidity

Using that glass and ice cubes will certainly give you an idea, but of course, you do not get accurate measurements.

That is when you have to invest in a hygrometer. Here is how to utilize it to measure the relative humidity in your room.

Fact: For comfortable living conditions in summer, keep the relative humidity in the house between 40 and 50 percent. 

Get a Hygrometer

hygrometer digital

Begin the process by shopping for a hygrometer. Hygrometers are widely available and can be obtained at any home improvement center, hardware store, or even online.

Hygrometers can be either digital or analog.

The relative humidity is displayed by a needle on an analog hygrometer, while on a digital hygrometer, the reading is displayed numerically. 

Place it Properly

Simply set up the hygrometer in your room, but pick your spot carefully.

Remember that nearby moisture sources like a shower or sink can impact the hygrometer’s readings. Therefore, it is best to keep it in a safer location. 

Acclimate the Hygrometer

The hygrometer needs time to adjust to the room’s temperature and humidity after being set up.

The time it takes to do so depends on the type of hygrometer being used and the ambient conditions in the room.

In most cases, it can range from a few minutes to many hours. 

Take the Readings

take the readings of humidity

In order to get an accurate reading of the humidity level, you must first allow the hygrometer to adapt to the environment.

When using an analog hygrometer, the relative humidity can be read off of where the needle lands on the scale.

Use a digital hygrometer to see the relative humidity readout instantly. 

Record It

Take note of the current relative humidity reading. Depending on the hygrometer, this can be done manually or electronically. 

Repeat the Process

The relative humidity of a room should be measured multiple times throughout the day and in varying weather conditions.

You will get a more precise reading of your room’s relative humidity and be able to take corrective measures. 

Adjust the Humidity

Room humidity may need to be adjusted if the relative humidity is either high or too low.

A humidifier can be used to raise the relative humidity in a space. A dehumidifier or air conditioner can be used to reduce the humidity level.

Fact: For comfortable living conditions in summer, keep the relative humidity in the house between 40 and 50 percent. 

Factors Affecting the Relative Humidity in a Room

When measuring relative humidity in your room, so many things can lead to inaccurate readings.

For instance: 


factors affecting relative humidity

Humidity is proportional to the temperature at which it is measured. Due to an increase in the air’s capacity to store moisture, relative humidity can decrease when temperatures rise

And, the opposite is true when temperatures drop, as the air’s capacity to store moisture reduces. This in turn can lead to higher relative humidity.

A reliable reading of relative humidity requires that the hygrometer be placed in a constant temperature environment


The presence of air movement may skew a room’s relative humidity readings.

A higher airflow is likely to affect the evaporation rate, which will cause the relative humidity to change as well.

This is why keeping the hygrometer away from open windows or vents is so crucial. 

Proximity to Water Sources

The accuracy of a hygrometer’s readings can also be affected by its location in relation to sources of water.

You may get higher readings if the hygrometer is placed too close to a water source like a shower or sink.

This is because the presence of the water source will add moisture to the air, resulting in inaccurate measurements.

Similarly, measurements of relative humidity can also be impacted by the presence of moisture sources like plants and aquariums.

Plants increase indoor humidity by transpiring water into the air.

In a similar vein, aquariums can impact humidity levels since they emit moisture into the air

Humidity Control Devices

humidity control devices

Measurements of relative humidity in a room can be affected by the usage of air conditioners, dehumidifiers, and other humidity control devices.

The relative humidity of a room can be altered by using either a humidifier or a dehumidifier, or by turning on the air conditioner.  

Fact: Humidity readings can be impacted by the hygrometer's precision, as you will get incorrect readings from a hygrometer with a deteriorating sensor.


How can I measure relative humidity in a room? You can simply learn about the humidity levels by considering condensation.

But for more accurate readings, you will have to use a hygrometer.

Be sure to place it correctly and always calibrate before use to measure relative humidity accurately.