wet window with leaves from humidity

How to Test Humidity Levels in Your House

Maintaining the proper humidity level in your house is crucial for your comfort, health, and for preserving your home’s structure and furnishings. But how can you tell if your indoor air is too dry or humid, and what can you do about it? This article will guide you through the importance of monitoring humidity, identifying the ideal levels, recognizing the signs of imbalance, and specifically, how to test the humidity levels in your home.

wet window with leaves from humidity

Importance of Monitoring Humidity

The humidity level in your home can significantly affect your health. Low humidity can dry out your skin and mucous membranes, leading to discomfort, respiratory problems, and increased susceptibility to infections. On the other hand, high humidity can create an environment conducive to mold and dust mites, triggering allergies and asthma.

Besides health concerns, the wrong humidity level can damage your home. Low humidity can cause wood to crack and warp, while high humidity can lead to mold growth and structural damage over time.

Ideal Humidity Levels

The Environmental Protection Agency (EPA) suggests maintaining indoor humidity levels between 30% and 50%. This range is optimal for human health and helps prevent the growth of mold, dust mites, and other pathogens.

Signs and Symptoms of Low Humidity

  • Physical Discomfort: Dry skin, irritated eyes, and scratchy throat.
  • Health Issues: Increased frequency of respiratory infections and static shocks.
  • Home Damage: Gaps in wood floors, cracked paint, and separated joints in wood furniture.

Signs and Symptoms of High Humidity

  • Physical Discomfort: Clamminess, sweating, and difficulty sleeping.
  • Health Issues: Exacerbation of allergy and asthma symptoms.
  • Home Damage: Condensation on windows, musty odors, and mold or mildew growth.

How to Test Humidity

  1. Hygrometer: The most straightforward method to measure humidity is with a hygrometer. This is a device that provides a digital reading of the humidity level. A capacitive sensor has a hygroscopic (water-attracting) dielectric material between its plates, which absorbs or releases water vapor as the humidity changes. This alters the capacitance of the sensor, which can be measured and converted into a humidity reading.

The ThermoPro TP50 is a very affordable and accurate option for measuring humidity and temperature indoors. But suppose you’re looking for something more advanced. In that case, the Govee WiFi Temperature Humidity Monitor offers remote monitoring via a smartphone app, which is very useful if you plan on having one in every room.

  1. Smart Home Systems: Many smart home thermostats and systems now include humidity sensors that can be monitored via a smartphone app, providing a convenient way to monitor your indoor climate.

Monitoring and maintaining the proper humidity level in your house is essential for your health and the longevity of your home and possessions. Understanding the signs of imbalance and using the right tools to measure humidity can create a more comfortable and safer living environment. Whether you opt for a simple hygrometer or a smart home device, staying informed about your home’s humidity levels is a step towards a healthier home.


1. What is the ideal humidity level in a bedroom?

Like the rest of your home, the ideal humidity level in a bedroom should be between 30% and 50%. This range is recommended for comfort and health, preventing the growth of mold and dust mites. Maintaining humidity within this range can help ensure a good night’s sleep and reduce the risk of respiratory problems or allergies.

2. What is the ideal basement or crawl space humidity level?

The ideal humidity level for basements and crawl spaces is also within the 30% to 50% range. However, due to their below-ground location, these areas are prone to higher humidity levels, which can lead to mold and mildew growth. Keeping the humidity level closer to the 30% end of the spectrum can minimize these risks and protect the structure of your home.

3. How big of a dehumidifier do I need?

The size of the dehumidifier you need depends on the size of the space you want to dehumidify and the level of humidity. Dehumidifiers are typically rated by how much moisture they can remove in 24 hours, usually measured in pints. For a moderately damp room (50-70% humidity) of up to 500 square feet, a dehumidifier that can remove up to 10-12 pints of water daily is usually sufficient. You’ll need a dehumidifier with a higher pint removal capacity for larger spaces or areas with higher humidity levels. Always refer to the manufacturer’s recommendations for the best results.

4. How big of a humidifier do I need?

Like dehumidifiers, the size of the humidifier you need depends on the area to which you wish to add moisture and the existing humidity level. Humidifiers are often categorized by the size of the area they can effectively cover, from small (personal or single-room) models to large (whole-house) systems. A small to medium-sized humidifier typically suffices for a single room, covering anywhere from 300 to 500 square feet. For larger areas or entire homes, you may need a console or whole-house humidifier that works with your heating, ventilation, and air conditioning (HVAC) system.

5. How long does it take for a hygrometer to read humidity levels?

Most digital hygrometers can provide an initial reading within seconds, but it may take up to ten minutes to stabilize and accurately reflect the room’s humidity level. For precise measurements or when using a new hygrometer, it’s a good idea to allow the device to sit in the environment for about 15 to 30 minutes to acclimate and provide a fully stable reading. Analog hygrometers may also require a similar period to adjust to the current conditions.

Lead Editor (IAQ), Clinical BacteriologistJessica Gunoskey
Jessie is the lead editor for Air Koality, overseeing all IAQ guides to ensure accuracy and quality. She holds a degree in Molecular & Infectious Disease Biology from Washington College in addition to working for multiple top-rated universities, such as UConn and UPenn. Not only does she write and edit, but she also is a STEM tutor and microbiologist!

Expertises: microbiology, infectious disease, biology, air quality

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