Section 1. Economic and business aspects of green retrofitting. Chapter 1. Business models for green retrofitting ; Chapter 2. Financial considerations in green retrofitting for optimal energy performance ; Chapter 3. Financing the green building retrofitting investments: a case study for a Romanian seaside hotel ; Chapter 4. Comparative analysis regarding the online interest of consumers towards green retrofitting: case study in Germany and Romania -- Section 2. Social aspects of green retrofitting. Chapter 5. Smart homes as a solution for sustainable and more inclusive retrofitting of existing buildings ; Chapter 6. Phenomena implied by sustainable and green retrofitting: a quantitative approach ; Chapter 7. Considerations regarding the green retrofitting of residential buildings from human wellbeing perspectives ; Chapter 8. Building information modeling for energy retrofitting -- Section 3. Technical and ecological aspects of green retrofitting. Chapter 9. Retrofitting for energy management: using IoT technologies ; Chapter 10. Green retrofit energy efficiency potential on existing building envelope for residential and non-residential building ; Chapter 11. Economic analysis for green residential and non-residential building envelopes ; Chapter 12. Heating systems: a comparative assessment of alternative solutions.