If you place your safe within a climate controlled home where the temperature remains constant and where condensation will not occur ...you may not need a dehumidifier. If there is any fluctuation in temperature condensation may occur. Moisture causes corrosion. Because most dehumidifiers are not costly we recommend that they are used in all safes... just in case. Place the dehumidifier as low in the safe as possible. Mounting position is not necessarily important, but it is vital to keep the door area clear of any obstruction. Installation along the back wall or underneath one of the small side shelves is the preferred method of installation.