Controlling Humidity Levels in Your Home

Summer is upon us, and in many regions of the country, humidity (the amount of water vapor in the air) has arrived with the hot summer air. High levels of humidity are generally uncomfortable for most people, but they can also cause damage to your home and, indirectly, to your health. Excess moisture can lead to pests in the home, and can damage ceilings, walls, and paint or wallpaper.

According to the Centers for Disease Control and Prevention, molds (fungi that are found both indoors and outdoors) grow best in damp, warm, humid conditions, and spread and reproduce through spores. Mold can cause major damage to your house and belongings, and people who are sensitive to molds suffer from symptoms including nasal stuffiness, wheezing, and skin and eye irritation. Controlling humidity levels, therefore, is an important aspect of maintaining both a physically sound, and a healthy home.

On the other hand, air that is too dry can cause cracks in furniture, drywall, and plaster, and can negatively affect paneling, wood trim, and hardwood flooring. In either case, controlling the humidity levels is important.


If you live in a humid climate, it’s a good idea to use dehumidifiers in your home, especially in damp areas such as basements. But how much moisture should you remove from the air? What is a good, healthy humidity level for your home and your family?

According to, “the recommended average relative humidity level is between 35% and 45%.” Although individual homes handle humidity levels differently, this range should provide a comfortable environment for the family, while protecting drywall, wooden furniture and belongings, and musical instruments. The EPA , meanwhile, notes that it is important to ventilate attics and crawl spaces to prevent moisture build-up, and that “keeping humidity levels in these areas below 50% can prevent water condensation on building materials.”

You can use an inexpensive hygrometer to monitor the humidity levels in your home. Some humidifiers have built-in gauges to measure humidity levels, and will automatically shut off or turn on depending on measured levels in the room. Air conditioners also remove humidity, and when it comes to damp bathrooms, notes that an open window or a ceiling exhaust fan can decrease humidity levels.

If you suspect or discover mold in your home, COIT offers a number of services that can help. Periodic Air Duct Cleanings will prevent your air duct system from becoming a breeding ground for mold spores, as well as bacteria, mildew, and other microbes. In cases of major water damage caused by flooding or burst pipes, or mold problems caused by dampness and/or humidity, our Emergency Restoration and Cleaning Services are available to homes and businesses 24 hours a day, 7 days a week. Just call 1-800-FOR-COIT.


If you live in a region where a dry environment is more of a problem than humidity, a humidifier will likely add the moisture you need. In some parts of the country, a dehumidifier will come in handy in the summer, while a humidifier will be needed when the cold, dry winter air returns. notes that it’s important to buy the right size humidifier for the room where it is placed, to avoid adding too much moisture to the air. Follow manufacturer instructions carefully regarding filter changes and cleaning to keep your humidifier in good working order. If you run a humidifier with a dirty filter, you actually could be adding mold spores or bacteria to your indoor environment.

For more information about choosing and operating humidifiers in your home, visit’s online FAQ.