The adaptive thermal comfort concept has been developed over many years and proven in numerous field studies (e.g. Webb 1964, Nicol and Humphreys 1973, Auliciems 1981b, de Dear et al. 1997, McCartney and Nicol 2002, Manu et al. 2016), showing that people are satisfied with a wide range of thermal conditions. Prerequisite is that people are provided with means to make themselves comfortable, that they know which opportunities they have, that it is socially acceptable to use these opportunities and that they are willing to use them (Hellwig, 2015). However, the overall understanding of how to design for such opportunities enabling the occupant to make themselves comfortable in relation to climate and building type, thus how to convert the adaptive thermal comfort concept into building design and concepts for operating buildings, is still limited. There are still common misunderstandings in the interpretation of the adaptive comfort approach among building planners and operators e.g. regarding the amount of control, the seriousness of this topic or the level of information needed by occupants for which reason guidance (e.g. CIBSE 2010, Cook et al. 2020) and knowledge transfer (e.g. Hellwig and Boerstra 2017, 2018) is absolutely essential. Consequently, there is still a gap between scientific research and real-world-application, which this report aims to diminish.In line with the activities within IEA EBC Annex 69 Subtasks A, B, and C, the present report includes four main sections, addressing the above listed identified challenges and barriers to the adoption of the adaptive thermal comfort in practice by explaining the adaptive thermal comfort principles, by illustrating the benefits from applying the adaptive principles in buildings, through guidance on how to implement the adaptive principles in the design and operation of buildings, especially providing guidance on how to design for adaptive opportunities. The Appendices contain additional information on standards, checklists for stakeholders in the design and operation of buildings as well as documentation and lessons learnt from the buildings investigated within this Annex 69 Subtask C. This report is formulated with the help of frameworks (Hellwig et al. 2019, Hellwig et al. 2020) developed to facilitate the adoption of adaptive principles in the design and operation of buildings. We aim to provide the knowledge on a general level of understanding, so that it is possible to apply the knowledge in different types of building usage, different climate zones and occupant groups. However, the majority of examples used in this report stems from office buildings, which is mainly rooted in the fact that the majority of research studies focussed on this type of building. Nevertheless, we have supplemented this report with examples from other building types. The target group of the guidelines in this report are building planners (architects, engineers, sustainability certification consultants/councils) and building operators (facility managers, operators, owners, and tenants). Furthermore, the guidelines in this report are intended as critical sources and guidance to educate future building professionals and stakeholders.The report includes four main sections, as outlined below.Section 2 summarises the three adaptive comfort principles, i.e. physiological, behavioural and psychological adaptation. The section follows with a discussion on the effectiveness of the adaptive principles and on the order of activation of adaptive responses. It ends with a brief account on the development of adaptive models.Section 3 describes the benefits from applying the adaptive principles in buildings, including energy savings, resilience to climate change, improved usability and thermal satisfaction, as well as improved health and well-being.Section 4 presents the developed framework for adopting the adaptive comfort principles in design and operation of buildings. The main elements of the framework are described, i.e. the building context, adaptive responses and actions, the building planning and design, –the adaptive opportunities design, and the operational planning and operation. Each of these subsections includes guidelines to facilitate the integration of adaptive principles. Section 4 ends with considerations and recommendations for adopting adaptive comfort in conditioned buildings, including advice for facilitating free-running mode in building operation as often as possible and ways to integrate the use of the adaptive principles in permanently or long-season conditioned spaces.AppendicesAppendix 1 summarises information on adaptive models used in international and national standards, as well as examples of models developed by research in various locations and climates.Appendix 2 provides checklists of parameters that can help stakeholders implement measures to ensure the availability of adaptive opportunities in buildings.Appendix 3 is a collation of case studies with practical learnings from adaptive buildings investigated in Annex 69 Subtask C.Appendix 4 lists publications, presentations and workshops related to Activity B2 of IEA EBC Annex 69.Authors of main report on guidelines, Appendix 1, 2, 4 worked out in Subtask B, Activity B2Lead: Runa T. Hellwig, Aalborg University, DenmarkCo-lead: Despoina Teli, Chalmers University, SwedenContributors:Marcel Schweiker, Karlsruhe Institute of Technology, GermanyRodrigo Mora, British Columbia Institute of Technology, CanadaJoon-Ho Choi, University of Southern California, USARajan Rawal, CEPT University, IndiaM.C.Jeffrey Lee National Taichung University of Science and Technology, TaiwanWang Zhaojun, Harbin Institute of Technology, ChinaFarah Al-Atrash, German Jordanian University, JordanAuthors of Appendix 3 Documentation of buildings investigated in Annex 69, Subtask CLead: Richard de Dear, University of Sydney, AustraliaCo-Lead: Stephanie Gauthier, University of Southampton, UK; Jungsoo Kim, University of Sydney, AustraliaContributors (in alphabetical order): Farah Al-Atrash, German Jordanian University, JordanLeonidas Bourikas, University of Southampton, UK Bin Cao, Tsinghua University, ChinaJoon-Ho Choi, University of Southern California, USAChungyoon Chun, Yonsei University, KoreaHeidi Creighton, Buro Happold Engineering, USAPaul Cooper, University of Wollongong, AustraliaJérôme Damiens, Tsinghua University, ChinaRichard de Dear, University of Sydney, AustraliaStephanie Gauthier, University of Southampton, UKRuna T. Hellwig, Aalborg University, DenmarkWenjie Ji, Tsinghua University, ChinaXinyu Jia, Tsinghua University, ChinaJungsoo Kim, University of Sydney, AustraliaSuhyun Kwon, Yonsei University, KoreaKyeongsuk Lee, University of Southern California, USA