As climate change poses significant challenges globally, the built environment’s contribution to greenhouse gas emissions is increasingly scrutinized. This chapter emphasizes the importance of effective building maintenance and refurbishment strategies to minimize environmental impact. In addition to exploring various maintenance strategies for reducing energy consumption and emissions, the chapter discusses the significance of building refurbishment and smart retrofits for sustainability. An examination of greenhouse gas emissions associated with the built environment is included, along with quantification and reporting methods based on the Greenhouse Gas Protocol. Further to addressing performance benchmarking on carbon emissions among buildings, the chapter outlines methods for conducting environmental and economic evaluations of energy retrofits, showcasing a credible procedure for assessing environmental benefits and related costs. Finally, an empirical case study illustrates practical applications of these evaluations, offering valuable insights for practitioners, decision-makers, and researchers striving for a more sustainable built environment.