The present paper describes the e-learning experience conducted by the University Network for Architecture and Sustainability (UNAUS) in its online courses. UNAUS main aim is to promote knowledge on environmental issues in architecture, building construction, restoration and urban planning. The topics of the online courses discussed here are Repair and Restoration for Sustainable Architecture, Building and Sustainability and GIS Techniques for Sustainable Development. This paper deepens in the educational methodology of these courses, focusing on one of the learning tools that characterize them, a transversal debate organized in each edition of the courses, and the benefits it provides. Thus, we describe and analyze the basic methodological criteria adopted for the organization of the debate: the role of the moderator conducted by an invited expert, the choice of a theme that cuts across the three courses and the open access to the debate are extremely enriching facts. The integrated and cross reflection on such a teaching experience and the results obtained allows important conclusions that expand the horizons of specific technical issues focused online courses.