A security housing contains a housing body having ventilation openings for supplying air to a heat source, in which air convection takes place for dissipating heat. First air guide elements are disposed in the housing body on a first side of each of the ventilation openings and are shaped for partly covering the ventilation openings. The first air guide elements each have a base integrally molded on the housing body, the bases are spaced apart from each other such that, in each case one of the ventilation openings is further defined. A removable security housing part is disposed inside the housing body and forms an air guide duct. Second air guide elements are disposed in the air guide duct and are shaped such that they cover the ventilation openings and the first guide elements such that, non-rectilinear air guidance is ensured.