Abstract The global quest for sustainability in the exploitation of resources and the need for carbon foot-print reduction has resulted in the development of a large number of innovations and a huge amount of knowledge on sustainable building technologies. Unfortunately, users are being overwhelmed with information overload in this area such that it is difficult for them to make informed choices. The emergence of Semantic Web technologies, the next generation of Web technologies, promises to considerably improve representation, sharing and re-use of information to support decision-making. This paper explores the extent to which emerging Semantic Web technologies can be exploited to both represent information and knowledge about sustainable building technologies, and facilitate system decision-making in recommending appropriate choices for use in different situations. This is done by undertaking a literature review of emerging Semantic Web technologies and emerging innovations in sustainable building technologies. To demonstrate what can already be gained from the Semantic Web, a conceptual model for representing information about photovoltaic system, a major type of sustainable building technologies has been developed. The model is used to develop and test a prototypical ontology in Web ontology language representing knowledge in the photovoltaic system domain. The ontology has been extended to include Description Logics that provide a reasoning mechanism to facilitate system decision support.