A developed service for smart home environments controls and coordinates a variety of appliances to influence physical environmental parameters selectively and to create a pleasant and activity appropriated room atmosphere. In the meaning of this paper this kind of service is defined as a composite service. There are several approaches to map services in ontologies. But these ontologies are not able to map composite services as they are introduced here. In this paper a possibility for mapping composite services with an ontology is presented. The composite services are defined on a devices landscape, with devices using exclusively DC voltage. The mapping of the composite services is done to promote compatibility to other systems. The paper’s scope is to show recent research activities and their partial results. Because the work is still in process final results are outstanding.