Indoor Humidity & Your Health

Indoor Humidity & Your Health

In the mold remediation world indoor humidity levels are a common topic of discussion. According to the EPA, “Indoor relative humidity (RH) should be kept below 60 percent—ideally between 30 percent and 50 percent, if possible.” In regions like Pennsylvania we experience a true winter which brings cold air. Because cold air holds less moisture than warm air, we get a major reduction in both outdoor and indoor humidity. These large swings in humidity can contribute to many potential health issues. Our customers are often familiar with the dangers of high humidity within their homes, but rarely do they know that too dry of air can be problematic as well. 

Beginning on October 1st and extending until April 30th is a time period often referred to as heating season. The most common way of heating a home in our climate is through a forced air furnace. Air is brought in from outside the home and heated up. The air is delivered throughout the house via supply ducts. It is then drawn back into the system through the return ducts to be reheated. This heating of the air does not add any humidity to the air (unless there is a humidifier on the furnace). What you are left with is months of bringing in dry outside air that continues to get heated. 

Indoor Humidity & Your Health
Mold Medics Home inspection

The entire indoor environment including the occupants, building materials, contents and the air all dry out during the winter months. Have you ever noticed static electricity, dry skin, dry hair, bloody noses or a dry throat during the winter? This drying of the indoor air can cause serious health issues. Low humidity in a home can be linked to dry irritated eyes, dry itchy skin and the drying out of the mucous membrane lining in your respiratory tract. 

A recent study performed by Yale University exposed mice to influenza A virus and housed them in chambers with either low or normal humidity. Science Daily published the study under the tile “Flu virus’ best friend: Low humidity.” According to the study, “The researchers found that low humidity hindered the immune response of the animals in three ways. It prevented cilia, which are hair-like structures in airways cells, from removing viral particles and mucus. It also reduced the ability of the airway cells to repair damage caused by the virus in the lungs. The third mechanism involved interferons, or signaling proteins released by the virus-infected cells to alert neighboring cells to the viral threat. In low-humidity environment, this innate immune defense system failed.”

The Yale study reveals glaring insights into just how much low humidity can affect occupants of buildings. “It’s well known that where humidity drops, a spike in flu incidence and mortality occurs. If our findings in mice hold up in humans, our study provides a possible mechanism underlying this seasonal nature of flu disease,” said Iwasaki. With this most recent incarnation of Coronavirus (COVID-19) many people are left helpless on what they can do moving forward. Monitoring your indoor humidity may be a potential way to set yourself up for optimal health moving forward. Along with the common recommendations of proper hygiene, sleep, nutrition, tobacco avoidance, etc. maintaining proper indoor humidity levels can be a piece to the puzzle of maintaining optimal health. Investing in several hygrometers (create hyperlink to hygrometer?) and placing them throughout your home is a great way to monitor indoor humidity levels. Once you are monitoring your indoor humidity it is important to either humidity or dehumidify the air to reach the desired humidity levels (30%-60%). On tips for raising your indoor humidity levels in the winter check out our previous article

Scroll to Top