Normal Basement Humidity Levels

Basements are prone to dampness and high humidity, which can make your whole house feel sticky and damp. Mold growth is also a common problem when basement humidity is high. Controlling moisture levels is the key to keeping humidity within normal limits in your basement.

According to Oregon State University, relative humidity is the amount of water in the air compared to the maximum amount it could hold at a certain temperature. Warmer air holds much more moisture than cold air, making humidity higher in warmer climates than in cooler ones. Basements tend to be higher in humidity because they are close to the soil where water evaporates. For a healthy, mold-free home, the Centers for Disease Control and Prevention recommend that homeowners keep the humidity levels in all rooms between 40 and 60 percent.

Basement humidity levels are often high due to water leaks, condensation and water evaporation. Many basements are carpeted, causing excess moisture when water leaks occur. During hot, humid months, basements often develop excess condensation which can lead to high humidity. Those living in arid climates may experience low humidity levels inside their homes. When humidity levels drop to a low level, residents may experience dry skin, sinuses and cracked lips.

Basements with high humidity levels often develop dust mites and mold growth. Harmful bacteria thrive in humid conditions and can make those who live in the home feel sick. Residents who are allergic to mold may experience symptoms such as nasal congestion, itchy eyes and skin rashes. Those with asthma or other immune-depressed conditions may experience wheezing, coughing, difficulty in breathing and dangerous fungal infections of the lungs. Homes with low levels of humidity are just as uncomfortable. Low humidity can cause dry sinuses and cracked lips.

Measure the humidity levels in your basement and throughout your house with a hygrometer, which closely resembles a thermometer and is available at your local hardware store. If the humidity levels in your basement are high, look for signs of water leaks and repair them. Putting a dehumidifier in your basement can help reduce condensation and bring humidity levels down. Place a plastic covering on dirt floor basements to prevent water vapor from seeping in from the soil and raising humidity levels. If your humidity levels are low, humidifiers can help raise them to normal levels. There are several different types of humidifiers available, including portable ultrasonic humidifiers and central humidifiers that are built into the heating and cooling system of your home.