For best humidity removal, placement of the unit does not matter since the humidity is equalized throughout the room; however placing the unit in the center of the room will get the room dehumidified faster.
Place the dehumidifier in a location that does not restrict airflow into the front coil or out of the top grille. The dehumidifier should be operated in an enclosed area to be the most effective. Close all doors, windows, and other outside openings to the room.
If the unit is in the basement, the dehumidifier will have little or no effect in drying an adjacent enclosed storage area, such as a closet, unless there is adequate circulation of air in and out of the adjacent area.
Never operate the dehumidifier in an area that is likely to accumulate standing water.