Vernacular architecture, as a significant part of the built cultural heritage, reflects the identity of a place. This is because, over time it has developed through a continuous process of adaptation, to meet the social, economic, and environmental needs and requirements of the society. Furthermore, our understanding of sustainability can be enriched through a holistic and interdisciplinary view of both the tangible and intangible values embedded in these vernacular dwellings. However, heritage and sustainability are usually studied and taught as separate fields, not necessarily connected to each other. Meanwhile, it is noted that despite the recent wide adoption of digital tools in universities, their use in the field of cultural heritage conservation is still deemed poor. In response to this need, this article describes the design of an online course on the topic of environmental conservation of vernacular architecture, developed in the framework of the Erasmus Plus programme ‘Smart Rehabilitation 3.0’. This Erasmus Plus programme aims to create new digital educational tools for cultural heritage conservation in order to address different types of challenges, as well as to present a new curriculum that takes a holistic approach to the field of conservation. The development of the aforementioned online course is divided into five modules, including an introduction and overview of the sustainable aspects of vernacular architecture (module I), a brief reference to environmental assessment tools (module II), an insight into traditional building materials (module III), as well as passive heating and cooling strategies (module V), and finally, an overview of the principles of environmental conservation through case studies (module V). The creation of this online course highlights the great opportunities for online learning and continued education in this field, in turn underlining the need to apply these tools to improve the sustainable features of vernacular architectural heritage.