According to an aspect of the invention a localization method for localizing a host device (100) in a control system, in particular a building control system, is provided, the localization method comprising determining geographical location information of the host device (100) by means of a localization device (102) and associating the geographical location information with a unique identifier of the host device (100). According to another aspect of the invention a computer program product is provided that comprises program instructions which, when being executed by one or more processing units, cause said processing units to carry out or control the steps of the inventive localization method. According to another aspect of the invention, a localization device (102), in particular a portable localization device is provided for use in the inventive localization method.