Humidity occurs by moist surfaces drying and that moisture evaporating into the air. Many items are constantly creating moisture and eventually evaporating into the air inside our homes and properties. A family of 4 produces approximately 25 pints of moisture per day during normal activities. Excessive humidity in a residential space can also result from any of the following if not properly controlled: Leaks, showering, hanging clothes to dry, boiling water for cooking, humid outside air, atmospheric conditions, breathing, improperly ventilated crawl space, not running the air conditioning during summer. Our IW25-4 in-wall dehumidifier is a reliable and proven way to manage humidity in homes.