Humidity levels inside a home should not exceed 30 percent in the winter or 55 percent in the summer, according to Home Energy Resource MN. The company provides a specific chart for different temperature levels.
According to the charts for winter temperatures, if the outside temperature is between 20 and 40 degrees Fahrenheit, then the inside humidity should not be over 40 percent. If the temperature was instead -20 degrees Fahrenheit or below, then the inside humidity should not be above 15 percent. These percentages are based on a 70-degree interior room temperature.
By maintaining these levels of humidity, condensation or frost can be prevented on windows. If there is too much moisture, mold may grow.
In the summer, the humidity levels can get too high in a home. Too much humidity and the introduction of cool air from air conditioning can cause condensation. It's suggested that the relative humidity should not exceed 55 degrees Fahrenheit in the main level of the home during the summer. If, for instance, the wooden floors are starting to buckle, this can be a result of too much humidity. A dehumidifier can be used to help dry the house out when necessary.