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What is humidity and why is it important?



What is humidity?

  • Relative humidity (RH) is the amount of moisture in the air compared to how much moisture the air can hold. The higher the RH, the more humid it feels. The warmer the air, the more moisture it can hold. That’s why it feels more humid in the summer.

Why humidify?

  • Cold air does not hold as much moisture as warm air. In cold winter months, a humidifier can add moisture to the room air, making the room feel more comfortable. Raising the humidity level in a cool, dry room also makes it feel warmer.

    The ideal humidity level is between 40-60%.


    Helps temporarily relieve dry air discomforts.

    Getting a good night’s sleep helps me feel healthier, more alert and ready to conquer the day. Washing all of our bedding every week on the hot cycle helps reduce allergens.


    Helps temporarily relieve congestion and cough.

    Maintaining an indoor humidity level between 40-60% can reduce the survival of flu viruses on surfaces and in the air*.


    Helps reduce
    static electricity.

    The pollen from the trees, grasses and weeds can stick to our skin, hair and clothing. I have learned that changing our clothes and showering when we come inside, can be extremely beneficial.


    Helps keep plants healthier.

    Using a humidifier helps return moisture to the air promoting plant growth.


    Helps you breathe better and sleep more comfortably.

    Comfortable humidity helps keep throat and nasal passages hydrated.


    Helps protect furniture.

    Low humidity causes wood to lose moisture and shrink. Extreme changes can causes warping and cracking.

*Studies have shown that keeping indoor air at an RH level of 40-60% reduces survival of flu viruses on surfaces and in the air compared to lower RH levels.


The Experiments: Observing Everyday Objects in Low Relative Humidity

  • Dry winter air may not be visible to the naked eye, but its effects can wreak havoc on everything in its path, including your skin and hair, as well as precious items in your home like family heirlooms, photographs and artwork. 

    In partnership with third-party environmental scientists from Environmental Heath & Engineering (EH&E), an environmental consulting and engineering services firm, EH&E placed grapes in a controlled low-humidity environment to show the impact to other items in the home. They quickly wrinkled, shrank and became dried out over time, showing how moisture can evaporate during cool, dry months. The findings underscore the importance of adding moisture to indoor air when relative humidity levels drop, to help reduce negative effects on similar items and on those living inside the home.

    "As cold temperatures set in during fall and winter months, humidity levels drop because cold air is unable to hold as much moisture as warm air. Indoor humidity levels can be as low as 10 percent- drier than the Sahara Desert," said Dr. Ted Myatt, ScD, who led the study by Environmental Heath & Engineering (EH&E). "These experiments show the value of maintaining optimum relative humidity levels between 40 to 60 percent. This can be done by using a humidifier to add moisture to the air to help alleviate the effects of dry air on the home and body, including dry skin and hair, similar to what was observed with the grapes."

    Find the right humidifier for you

    Humidity Experiment

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