The recommended indoor humidity level for homes is between 35 and 45 percent; this range creates the most comfortable environment in the home. This level of humidity helps to protect furnishings, drywall and other belongings from damage caused by dryness or excessive moisture.
The relative humidity in a house changes based on climate and air temperature. The way humidity affects a home also depends on the design of the house, its construction, its vapor barriers and how airtight it is. An excessive amount of moisture in the home shows there is too much humidity. Moist air is trapped in closed spaces, corners and basements, causing an increase in mildew and bacteria in the home. Condensation accumulates on windows and causes rotting around the frame as it pools. Heating moisture-laden spaces and using a dehumidifier decreases the level of humidity in the home and returns the space to its proper moisture level.
Heating systems can lower the level of humidity in the home, making the space too dry. Low humidity causes wood to splinter and crack and makes the space uncomfortable for its inhabitants. Using a humidifier in the home adds extra moisture to the air to create a comfortable living environment with proper moisture levels.