Indoor Humidity – How To Measure Home Humidity

how to measure home humidity

Maintaining a proper humidity level indoors is vital. When there is too much moisture in the air is can promote the development of mold and mildew which can trigger allergic reactions. Too little moisture in the air we breathe can result in dryness that can irritate the eyes, nose, and respiratory system. This is why it is so important to keep your home at the optimal indoor humidity level.

Fortunately, there are many ways to monitor and control humidity. In this article, we will look at how to measure home humidity and explore factors that must be considered in maintaining the ideal indoor humidity.

How To Measure Humidity In Your Home

Digital Hygrometer

The most common instrument used to measure home humidity is a digital hygrometer. The simplest type of hygrometer measures just relative humidity (RH) in a percentage value. They are inexpensive and accurate. Most come with other features built-in, including temperature readings, clocks, as well as high/low alarms.

These work by using either a capacitive or resistive device. A small electrical current passes through a material that absorbs moisture in the air. The electrical properties of this material change as the moisture levels in the air change. This affects the current that passes through the material, which then can be used to extrapolate the amount of humidity in the air.

Analog Hygrometers

Analog Hygrometers are also a very popular way to measure home humidity levels. These typically use a coil that is made from a strip of metal bonded to another material that absorbs moisture. When the moisture-absorbing strip absorbs moisture out of the air, it expands; however, the metal strip doesn’t and remains a constant length. This causes the coil to tighten or loosen depending on how much the moisture-absorbing strip expands or contracts.

The coil is connected to a needle, which causes the needle of the analog hygrometer to move to indicate changes in humidity.

The Ice Cube Method

While this is far from precise, the ice cube method will give you an approximation of how to measure humidity in your home. All you need to do is fill a glass with water and place two or three ice cubes into it. Give it about four minutes then check the condition of the glass. If it has condensation on the outside of the glass, the humidity may be too high. If there is no condensation, your humidity is too low.

One thing to remember when conducting this test is to not do it in a kitchen as cooking vapors can impact the results.

The Wet/Dry Bulb Method

Another method used on how to check home humidity level is with the use of two glass thermometers. One you will leave as is as it will be the dry bulb. For the other one, you will wrap a moistened cotton ball (using room temperature water) around the bottom of the instrument keeping it held in place by an elastic band. This will be your wet bulb.

Place both side-by-side on a piece of cardboard and leave for about six minutes. Record the temperatures, subtract the wet-bulb value from the dry bulb to get the depression value. Compare these stats to a chart that can be found online and you will learn the RH.

The Human Hair Method

As the name suggests, this type of hygrometer uses human hair. The hair is securely connected between 2 points. As the strands either expand or contract, they move a needle around a dial that indicates the RH percentage.

You can do this yourself with your own hair. All you will need is a long strand that you blow-dry. This will cause the strand to shrink. Measure the length and this will give you a baseline for 0% moisture. Then spray the strand of hair with water. It will expand and by measuring it at this point you will have an approximate length representing 100% RH. Measuring the hair after it sits in a room for a period will give you a length between the two extremes from which you will be able to estimate the RH %.

The Pine Cone Method

Although this method is not very effective for home humidity levels, it will demonstrate one way to measure relative humidity outdoors. Pine cones are either closed tight or open. When the air is dry, pine cones open to release spores. These spores will fall to the ground or be transported many miles in windy conditions. This is essentially how new trees start growing.

When the air is moist, or the humidity level is high, pine cones will be closed tight holding and protecting the spores from the elements. Forest fires assist trees in spreading spores to reforest fire-damaged areas.

Where To Place A Hygrometer In Your House

As mentioned above, the kitchen is not a good place to monitor humidity. Not only is it typically the busiest room in the average home, but steam and other vapors that are released in the air from stovetop cooking will prevent you from gathering accurate measurements.

Even the most expensive hygrometer will be affected by the excess moisture that can accumulate in a kitchen. So, if you want to know where to place a hygrometer in your house, it is generally best to use a room that is unoccupied, with little or no movement to get a proper humidity reading.

What Is Considered A Comfortable Humidity Level?

home humidity

That depends on the time of the season and your local climate. However, the ideal indoor humidity during the warmer months of Spring and Summer should be between 40 and 50%. If the humidity increases to above 60%, your home may feel uncomfortable. The high humidity value could make your home muggy with the extra moisture in the air.

As for the cooler months of Fall and Winter, the optimal indoor humidity level would be between 30 and 40%. Humidity that falls below 40% will keep condensation from collecting on windows but too low will cause your home to feel dry.

How To Control Home Humidity

Here is a list of ways to keep home humidity levels at the proper range, regardless of what time of year it is:

How To Lower The Humidity In Your Home

  • use exhaust fans in the kitchen and bathroom to remove excess moisture
  • purchase and use a dehumidifier
  • add house plants to your home as they are natural absorbers of excess humidity
  • try not to boil water on the stove as this adds additional moisture to the air
  • either reduce the length of your showers or use colder water
  • hang clothes to air dry (preferably outside) as using a dryer (especially if it is not vented outside) increases humidity
  • keep filters clean in all air conditioning units

How To Increase Home Humidity

  • purchase and use a humidifier to add moisture to the air
  • dry clothes on an indoor clothes rack as they will release moisture as they dry
  • add house plants to your home as they transpire, adding moisture to the air
  • when having a shower, keep the bathroom door open to let the steam move into your home
  • increase your stovetop cooking and boiling water on the stovetop as well
  • spray water into the air with a spray bottle

Sometimes Hygrometers Fail

One thing to keep in mind as you learn how to measure home humidity is that sometimes hygrometers do not provide proper readings. This is why we have included several alternative methods on how to check home humidity levels.

There are several ways in which a hygrometer can produce faulty readings. Here is a short-list of troubleshooting tips to help you determine if your measuring device is working properly should you suspect that it is not working correctly or does not produce consistent readings:

  • confirm that it has been calibrated correctly
  • compare readings with another hygrometer
  • ensure that the hygrometer is on and all sensors are correctly connected to the unit
  • confirm that the instrument and conditions it is measuring have stabilized
  • check the temperature if you are tracking RH
  • go over your records to see if maybe human error is the cause.

How To Control Home Humidity – Conclusion

Now that you know how to measure home humidity, and what is considered to be a comfortable humidity level, you should be able to keep your home from becoming too dry or too humid.

It isn’t hard to regulate RH when you know how to increase home humidity or how to decrease it using the tips mentioned above. Knowing how to measure home humidity is quite easy, so keep your home a safe and comfortable space for you and your family.

Leave a Comment