Normal Basement Humidity Levels
A comfortable basement should maintain a humidity level of 30 to 50 percent — however, those may differ depending on your climate.
Is 60% humidity too high for a basement?
Indoor relative humidity (RH) should be kept below 60 percent — ideally between 30 percent and 50 percent, if possible. ... Low humidity may also discourage pests (such as cockroaches) and dust mites.
Is 70% humidity high in a basement?
A relative humidity level of 70 percent or higher creates the perfect breeding ground for mold growth. Leaving basement mold unchecked could amount to unhealthy indoor air, causing sickness to your family and aggravated upper respiratory issues.
