An advection fan includes a housing having a metal housing base and a closure member. A lateral wall is arranged between the metal housing base and the closure member and includes an air inlet and an air outlet. A horizontal air passage is defined between the metal housing base and the closure member. The metal housing base includes an engagement section. A stator includes a coil unit embedded in or abutting and attached to the engagement section of the metal housing base. The coil unit abuts the engagement face of the metal housing base. The coil unit includes a substrate and at least one coil formed on a surface of the substrate by a printing circuit or electroforming process. An impeller is rotatably coupled to the shaft tube of the stator. A gap is formed between the impeller and the coil unit of the stator.