A dehumidifier removes moisture by drawing air into the unit across a set of cold coils where is condensed into water and allowed to drain. This dried air then passes over hot coils which make it slightly warmer. If you have a properly sized air conditioner, you shouldn’t need a dehumidifier to lower humidity, unless the air is too humid at times when it’s too cold to run the AC. The problem today is that properly sized HVAC systems are not available for many common residential situations, creating a need for dehumidification to augment the existing HVAC system. The IW25-4 In-Wall dehumidifier provides the ideal solution to combating residential mold growth.