A fan housing of a fan unit includes a housing wall standing from the surface of a printed circuit board. The printed circuit board serves to establish the fan housing in cooperation with the housing wall. The fan housing further includes a ceiling wall connected to the housing wall. The ceiling wall extends along a datum plane parallel to the surface of the printed circuit board. A high speed airflow can be generated within the fan housing. The airflow promotes the heat radiation from the printed circuit board. An electrically conductive wiring pattern extending over the surface of the printed circuit board may further promote the heat radiation from the printed circuit board.