How To Measure Humidity In House (Without Hygrometer) - Fresh Air Guru (2024)

If you’re looking for ways on how to measure humidity in house, then this guide is exactly what you need. An overabundance of moisture in a living space can trigger mold and mildew or lead to health conditions such as allergies or related respiratory distresses.

While a hygrometer is normally used to check moisture levels, you can use alternative methods as well. To ensure comfort, the humidity in your dwelling should register between 40% and 50%.

To learn how you can ensure this type of comfort, you need to learn more about humidity so you can accurately measure it. Definitively, humidity represents the moisture level in the air.

A hygrometer quickly reads the moisture by showing the percent of humidity in the environment. While this method is quick and effective, you may not have a hygrometer at the ready. Therefore, the following options can serve as substitutes.

How To Measure Humidity In House

Using Ice Cubes

To apply this method, take four ice cubes and a glass of water. This technique shows how dry and humid the air is in your home. Simply plunk the ice into the glass of water and set the glass in a room where you believe that the moisture level may be too low or too high.

Just do not place the glass in the bathroom or kitchen where the moisture levels are not the same from time to time. Place the ice cubes and water on a table in the room and quickly exit as too much movement can impact the outcome.

Leave the water and cubes in the room for about five minutes. Inspect the glass. If condensation has formed on the outside of the glass, the moisture level is high.

To absorb the excess, you may want to consider adding plants that readily absorb atmospheric moisture. If the glass shows no signs of condensation, you may want to add a humidifier. Dry air can lead to health concerns as well, such as skin conditions, eczema, or headache pain.

Perform the Wet and Dry Bulb Temperature Test

Another easy way to figure the humidity is to use two old-fashioned thermometers (the kind with mercury and glass tubing). Use one of the thermometers as a “wet bulb” thermometer and use the other thermometer as a “dry bulb” measure.

Before proceeding with the experiment, shake the mercury in each thermometer so it settles in the bulb of each device. Moisten the wet bulb thermometer with a dampened piece of cotton, affixing the cotton to the thermometer’s bulb.

Use room temperature water for the experiment. Next, place and duct tape the wet bulb thermometer and dry bulb thermometer on a piece of cardboard. The bulbs should project outwards.

Switch on a fan where you want to check the moisture level, pointing it toward the thermometers. Allow the fan to run for about five minutes. After this period, check the temperatures on each thermometer.

Subtract the temperature for the wet bulb thermometer from the temperature of the dry bulb thermometer. For example, on the Celsius scale, a difference of 10 degrees Celsius, also called the depression value, shows the percentage of humidity.

To arrive at this value and the percentage, refer to a table that lists the percents of relative humidity. Tables are featured online that show the relative humidity (RH) in percentages using the wet and dry bulb measure. Examples can be found, for instance, on the Engineering ToolBox site online.

Use Your Hair as a Hygrometer

The hair expands when it is exposed to excess moisture and contracts in dry climates. Based on this scientific fact, you can tell if the air is dry or moist by checking a strand’s length.

When the air dampens, hair increases in length; when the air lacks moisture, hair decreases in length. To check this out, you need to draw an arrow. Cut out the arrow and insert at the bottom.

The hole should be slightly larger than the needle of a pin. Pin the arrow on a piece of cardboard, making sure that it can easily spin. Wrap a strand of hair around the pin and pin it above the arrow on the cardboard.

Secure the other end of the strand around the arrow. Blow dry the strand first for about a minute. The hair will shrink, causing the arrow to move upwards. This represents a point for 0% moisture.

Next, spray water on the strand. Doing so will cause the arrow to move down, indicating 100% humidity. By referencing these points, you can determine the amount of humidity in the air.

By using the above methods, you will find out how humidity is important in terms of atmospheric comfort. Indeed, measuring the humidity level is relevant as this measurement is used in a large number of testing, storage, and manufacturing processes.

Humidity measurements are required in places where a need exists to reduce the level of condensation, prevent corrosion, or stop the formation of mold.

Excessive humidity can also lead to spoilage or the warping of materials. Therefore, this scientific measure plays a huge role in the manufacture and shipment of pharmaceuticals, fuels, chemicals, paper, and wood.

Air-conditioning systems frequently control humidity levels using a good deal of energy to remove the vapor in the air. Therefore, this measurement, when used to balance moisture levels, contributes to reducing energy costs and maintaining the proper environmental conditions.

The Pine Cone: Another Type of Hygrometer

One of the natural hygrometers in nature is the pine cone. The cone opens when the air is dry to release its spores. While you cannot test the humidity in a room with this natural hygrometer, the amount of moisture in the air can be shown to impact both indoor and outdoor activities and developments.

Some Basic Concepts

To understand the measurement of moisture, you also should consider some basic concepts. For example, water vapor reacts similarly to a gas and condenses to form either ice or water, depending on the temperature.

Even if it does not condense, water vapor can still penetrate materials or react to certain surfaces. The capacity of a space to hold moisture depends on the temperature. Higher temperatures hold more moisture than colder temperatures.

Relative Humidity

When measuring humidity, keep in mind that it can be expressed in one of varying ways. For example, the relative humidity is the most frequently used measurement.

Relative humidity is typically expressed in the form of a percentage with the following symbol – %rh. The interaction of a water vapor with certain materials forms the basis for relative humidity readings.

The Dew-Point Temperature

Dew point, or the dew-point temperature reading, is another way that humidity is read. The dew point represents the temperature at which dew occurs if a gas cools. Dew point measures provide the following information:

  • The reading shows what temperature to maintain a gas to avoid condensation.
  • This reading is a precise and overall measure of gas humidity, regardless of the temperature. Therefore, it directly relates to the amount of vapor present.
  • Dew point is always expressed in the form of a temperature reading. If the temperature goes below the freezing point, the term frost point applies.

Using a Ratio or Fraction as a Measurement

A ratio or fraction expresses the amount of water vapor within a gas. This measure may represent the volume of a substance or be registered in terms of mass.

Concentrations of Vapor

A concentration of water vapor shows the mass of vapor for each unit volume. For instance, the air in a space may contain about 10 grams of vapor for each cubic meter of space.

Other Points to Consider

You should also consider these other important concepts:


When a space or a gas holds the optimum water vapor at a certain temperature, it is classified as being saturated. If additional water is added to the saturated gas or if the temperature falls, the vapor condenses.

Partial Pressure

Partial pressure represents another measure of water vapor. For example, air, which is a gas mix, is made of pure gas elements such as nitrogen and oxygen.

The total sum of this type of gas is stated in terms of the total of the partial pressures. The air in a room may contain a partial pressure of water vapor that reads 1,000 pascals (Pa).

Super-Cooled Water

Water that is supercooled below the freezing point may develop dew, which appears in this form of water occasionally. The dew eventually freezes to ice.

Sensing the Humidity in the Air: Types of Measuring Devices

Now that you understand a little about water vapor concepts, you can see how hygrometer-type measurements are used to sense humidity.

For example, the aforementioned wet-and-dry bulb thermometer measurement senses the humidity by determining the evaporative cooling on a wet surface.

Color Changes

You can also determine moisture levels though changes in color. For example, inks or crystals that contain cobalt chloride or similar chemicals change their hue when excess moisture exists. You can also use a relative humidity sensor to find the relative humidity.

The device indicates an electrical change when water vapor is absorbed into a polymer type film. A dew-point probe also uses electrical change to measure the absorption of humidity into a porous metal oxide type of film.

Weighing Masses of Water

A gravimetric may be used, too, to weigh a mass of water, which increases and decreases based on a sample of humid air. Mechanical means such as the above-mentioned hair sample measure water by calculating the dimensional change in humidity-sensitive materials. Besides hair, polymers or paper can be used.

Light Can Be Used to Sense Humidity Too

An optical fiber can also support changes in humidity with the transmission or reflection of light. This is done by experimenting with an optical grating or hygroscopic coating.

Some scientists use a quartz crystal resonator to learn more about changes in resonant frequency produced by a mass of surface-absorbed water. Zirconia can also be used as a measurement. The amount of humidity is derived from the amount of oxygen in a gas.

Questions to Ask

When measuring humidity, you need to consider the following:

  • Do you want to measure the dew point or relative humidity?
  • What do you want to use for a humidity range and temperature range? Certain products will not survive extreme conditions such as hot or wet climates or very dry environments.
  • Does contamination exist? Dust or chemicals can prove to be hazardous to the health, depending on the humidity level.

Points to Keep in Mind

When making any type of humidity measurement or determining the moisture level in a room, you need to keep the following in mind:

  • The appearance of water droplet or any type of stray water may give you the wrong humidity results.
  • Always watch out for dust as it can lead to the wrong reading or calculation.
  • Check pressure differences with respect to the dew point or temperature variations with respect to the relative humidity.

When Hygrometers Do Not Work

You may want to use the makeshift tools described above instead of a hygrometer as hygrometers are not fail-proof. Sometimes the readings are not correct. If you suspect problems along these lines, you need to do the following:

  • Make sure that the equipment is switched on properly and everything is connected.
  • Find out if the instrument and the conditions are stabilized.
  • Check the temperature if you are recording the relative humidity.
  • Check the calibration.
  • Compare the reading of the gauge with another hygrometer.
  • Review any human mistakes such as recording errors or numbering mistakes.

Making Calculations

It helps to bone up on math as well when you are figuring humidity readings. Different methods are used to determine the moisture level in terms of dew point, vapor pressure, or relative humidity.

If you do have access to a hygrometer, the instrument usually comes with a software to make moisture conversions. Whether you use the software or not, you should have a basic understanding of how this type of measure is figured.

For instance, when relative humidity is expressed in a percentage, it takes the actual vapor pressure and divides it by saturation vapor pressure at the actual temperature and pressure.

This amount is multiplied by 100. This equation shows that the relative humidity represents a fraction of the water saturation at a certain temperature.

Once you find out more about the concepts of humidity and the various ways that it can be calculated, you will find that any tool used for measuring moisture can be put to good use.

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How To Measure Humidity In House (Without Hygrometer) - Fresh Air Guru (2024)


How To Measure Humidity In House (Without Hygrometer) - Fresh Air Guru? ›

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.

How can you tell how much humidity is in your house without a hygrometer? ›

The Ice Cube Test:*
  1. Place two or three ice cubes into a glass, add water and stir.
  2. Wait three to four minutes.
  3. If moisture does not form on the outside of the glass, the air is too dry; you may need a humidifier. If water has condensed on the outside of the glass, the level of relative humidity is high.
Mar 3, 2023

How can I tell how much humidity is in my house? ›

Using a hygrometer is the easiest way to measure the humidity in your home. The device measures humidity and temperature and is easy to use as a simple thermometer.

Can my phone check humidity? ›

Using the Barometer & Altimeter App

Barometer and Altimeter is a free Android app that reports the temperature and humidity using your Android's built-in sensors. If your Android does not have built-in sensors, the app uses your GPS to find the temperature and humidity based on a nearby weather station.

What is the most accurate way to measure humidity? ›

A hygrometer is a device used to measure humidity. Hygrometers come in both analog and digital versions, but modern, digital hygrometers are more accurate, so they are the most commonly used today.

Can iPhone check humidity? ›

You can also use the Apple Home app on an iPad or iPhone to view the current readings. Here's how to see the temperature or humidity in your home — this works when you are away from home, too. Open the Home app on your iPhone, iPad, or Mac. Tap Climate in the top shortcuts row.

Is 60 humidity too high in a house? ›

When the indoor humidity level is below 30 percent, the air is too dry, which can harm both a home's structural integrity and the homeowners' health. Conversely, when the level is above 60 percent, the air is too wet, which is also harmful to both the home and the homeowners.

What percentage of humidity is OK in a house? ›

The ideal relative humidity for health and comfort is somewhere between 30-50% humidity, according to the Mayo Clinic.

Is 70% humidity high in a house? ›

Research from the Building Science Corporation found that humidity of 70% or higher adjacent to a surface can cause serious damage to the property. The Health and Safety Executive recommends that relative humidity indoors should be maintained at 40-70%, while other experts recommend that the range should be 30-60%.

Is there an app for indoor humidity level? ›

uHoo. The uHoo Smart Indoor Air Quality Sensor provides information regarding PM2. 5, CO2, Carbon Monoxide, and VOC's. It also monitors temperature and humidity indoors and is compatible with Alexa and Google Assistant, working equally as well for iOS and android systems.

How can I measure humidity without a gauge? ›

Measure for optimal humidity for house – ice cube method

Here's what to do: Pop two to three cubes of ice in a glass with water. Leave for four to five minutes. Check the results – if the glass is dripping with condensation that's an indicator that humidity levels are high.

What are 2 ways that humidity is measured? ›

Humidity can be measured in two ways: Absolute humidity is the amount of moisture present in a particular volume of air and is typically measured in g/kg. Relative humidity (RH) is the relationship between the actual amount of moisture present and the maximum amount the air could contain.

How can I lower the humidity in my house? ›

Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce moisture in the air, but be sure that the appliances themselves don't become sources of biological pollutants. Raise the temperature of cold surfaces where moisture condenses. Use insulation or storm windows.

How can I reduce humidity in my home? ›

  1. Turn Up the AC. Your air conditioner will naturally decrease the humidity in your home by removing warm air and introducing cool air. ...
  2. Use a Ventilation Fan. ...
  3. Get a Dehumidifier. ...
  4. Cool Your Jets. ...
  5. Fix Your Leaks. ...
  6. Get Your Mind in the Gutter. ...
  7. Get a Clothesline. ...
  8. Move Your Plants.
Jul 27, 2022

Is 57% humidity too high in a house? ›

But what is high humidity? According to Energy Star, the ideal indoor relative humidity should be between 30 and 50 percent–anything higher than 50 percent is considered high. High humidity levels and excessive moisture can cause discomfort and health issues, and it can even wreak havoc on a home.

Does running AC fan reduce humidity? ›

Leaving your AC fan set to ON allows the moisture in your home to accumulate and reach mold-growing levels of humidity. To ensure that you and your family stay cool and healthy this summer, keep your AC thermostat fan setting to AUTO.

Why is my house so humid even with air conditioning? ›

The evaporator coil inside the indoor cooling unit can freeze during the summer, causing the home to feel more humid. Ice and frost on the coil surface prevent the refrigerant within from absorbing heat to lower air temperature and remove moisture from the air.

Is 50% humidity too high in a house? ›

Ideal in-home humidity levels should hover around 45%.

Anything under 30% is too dry, and over 50% is too high.

Is 55% humidity too much in a house? ›

Comfortable levels of humidity range between 30% and 60%, however, the ideal humidity level, according to ASHRAE, is between 45% and 55%. Anything above 55% is considered to be high.

What humidity does mold grow? ›

Water Vapor

If there are no cold-condensing surfaces and the relative humidity (RH) is maintained below 60 percent indoors, there will not be enough water in those materials for mold to grow. However, if the RH stays above 70 percent indoors for extended periods of time, mold will almost certainly grow.

Does AC increase humidity? ›

Your air conditioner naturally reduces humidity in the home because cool air holds less moisture than warm air. However, the system can't effectively pull moisture from the home if it's not running.

Is 80% humidity high for a house? ›

A home should have a relative humidity of 30% to 60%. Above 60% and you have what's considered “high” humidity. Besides being less comfortable, high humidity causes a host of other problems in your home, including: Growth of fungus and mold in various parts of the home.

Does opening windows reduce humidity? ›

During the winter, if you open the window when the outside air is colder than the air indoors, the cold air will come into contact with the warmer air and the level of humidity will fall automatically.

How do I know if my house is moist? ›

The Telltale Signs of Moisture Problems In Your Home
  1. Musty Odors from Mold and Mildew. ...
  2. Visible Mold or Mildew. ...
  3. Rotten Wood. ...
  4. Sticking Doors and Windows. ...
  5. Floorboard Issues. ...
  6. Bubbling or Peeling Wallpaper or Paint. ...
  7. Water Stains On Your Ceiling.
Mar 8, 2018

Where is the best place to put a humidifier in your house? ›

With a whole house humidifier, choose the most central room in your home, which is usually the living area. The idea is to get the unit where it can distribute the most humidity into the largest areas of the house. Placing the unit near a cold air return will help distribute the humidified air more thoroughly.

How do I know if my house needs a humidifier? ›

How to Know If You Need a Humidifier
  1. Dry and Itchy Skin. Your skin is one of the best indicators that your home humidity levels are off. ...
  2. Congestion and Nose Bleeds. Listen to your nose, too. ...
  3. Too Much Static Electricity. Humidity goes a long way in blocking static electricity and buildup.
Oct 28, 2020

What is the best number for indoor humidity? ›

Ideal humidity – and signs of trouble

Every home is different, but a level between 30 and 40 per cent humidity is typically ideal for keeping your home warm and comfortable in the winter, without leaving condensation on the windows. In the summer, that level can be higher, between 50 and 60 per cent.

Is there a humidity sensor? ›

The humidity sensor is a device that senses, measures, and reports the relative humidity (RH) of air or determines the amount of water vapor present in gas mixture (air) or pure gas.

What are the three ways to measure humidity? ›

There are three main measurements of humidity: relative, absolute and and specific. Absolute humidity (units are grams of water vapor per cubic meter volume of air) is a measure of the actual amount of water vapor in the air, regardless of the air's temperature.

How do you know if its 100% humidity? ›

If the air is totally saturated at a particular level (e.g., the surface), then the dewpoint temperature is the same as the actual air temperature, and the relative humidity is 100 percent.

What are the four method to determine humidity? ›

There are other methods which depend on the influence of humidity on the physical properties and behavior of various substances.
  • Measurement of Dew Point. ...
  • Measurement of Wet and Dry Bulb Temperatures. ...
  • Chemical/Physical Absorption Methods. ...
  • Electrical Conductivity Measurements. ...
  • Hair Hygrometer. ...
  • Thermal Conductivity Meters.

How much water is in the air at 70 humidity? ›

Weight of water vapor in air
Water Vapor in Air (pounds water vapor per pound dry air)
Relative Humidity (%)Temperature
10 more rows

What object do you use to measure humidity? ›

hygrometer, instrument used in meteorological science to measure the humidity, or amount of water vapour in the air. Several major types of hygrometers are used to measure humidity.

What is the alternative of hygrometer? ›

As Hygrometer is used to measure the Humidity in air, Similarly, A barometer is used to measure Atmospheric pressure. Hence, Atmospheric pressure is the correct answer.

Can you make a hygrometer? ›

To construct this hygrometer, you will need two thermometers, some cotton gauze, a rubber band, a small container, some water, and a piece of cardboard large enough to hang the two thermometers. Cover one thermometer with wet gauze.

How can I measure humidity without a meter? ›

Measure for optimal humidity for house – ice cube method

Here's what to do: Pop two to three cubes of ice in a glass with water. Leave for four to five minutes. Check the results – if the glass is dripping with condensation that's an indicator that humidity levels are high.

What is the least accurate way to measure humidity? ›

Many people believe the relative humidity is the best way to measure the humidity, but in most cases, it is the most inaccurate way to measure how the air feels. The term relative humidity can be explained as the closeness the air is to saturation.

What is the best app to check humidity in room? ›

uHoo. The uHoo Smart Indoor Air Quality Sensor provides information regarding PM2. 5, CO2, Carbon Monoxide, and VOC's. It also monitors temperature and humidity indoors and is compatible with Alexa and Google Assistant, working equally as well for iOS and android systems.

What causes high humidity in a house? ›

Water can enter your home by leaking or by seeping through basement floors. Showers or even cooking can add moisture to the air in your home. The amount of moisture that the air in your home can hold depends on the temperature of the air. As the temperature goes down, the air is able to hold less moisture.

What should the humidity level be in a house in the summer? ›

Most experts say that the ideal house humidity should be between 30 and 50 percent, but definitely below 60 percent in the summer months.

What is the best place to put humidity sensor in a room? ›

The sensor should be out of the direct beam from spotlights, away from sources of radiant heat, or cold, such as windows and poorly insulated outside walls. It should not be in the flow of convective air from a radiator. It should not be in the direct path of air blown in from an air conditioning duct.

Is 70% humidity too high for house? ›

Research from the Building Science Corporation found that humidity of 70% or higher adjacent to a surface can cause serious damage to the property. The Health and Safety Executive recommends that relative humidity indoors should be maintained at 40-70%, while other experts recommend that the range should be 30-60%.

Is 40% humidity too high for a house? ›

Research shows that the ideal relative humidity for your home is between 40%-60%. However, to discourage the growth and spread of mold, levels should be kept below 50%.


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