A fan assembly includes a first guide, a second guide disposed in a direction vertical to the first guide such that the height of the first guide is adjustable, a slider disposed to move in a horizontal direction along the second guide, and a plurality of fan modules fastened to the slider, wherein each of the plurality of fan modules is fastened to the slider such that the height of the fan module is adjustable. Accordingly, the heights of the plurality of fan modules can be simultaneously adjusted, and the heights of some of the plurality of fan modules can be adjusted different from those of the other fan modules, so that the plurality of fan modules can be optimally installed.