A Revit-Energy Plus Methodology for Carbon-Negative Retrofit of Existing Residential Buildings

The proportion of carbon emissions from the global building sector in energy-related carbon emissions has remained high for a long time, and existing buildings, due to their large scale and low energy efficiency, have become a key area for low-carbon transformation. Faced with the reality of high heating energy consumption and urgent need for renovation in frigid climate zones, promoting building energy efficiency upgrades and life-cycle carbon reduction has become an important path for green development. This study focuses on a public building built in the 1990s in Tieling County, Liaoning Province, addressing its problems of insufficient thermal insulation performance of the building envelope, poor indoor comfort, and high energy intensity, and conducting a systematic energy-saving renovation and life-cycle carbon reduction study. Through a dual-path strategy of low-carbon material substitution and energy efficiency improvement, the project achieved significant results: a 40.9% reduction in total carbon footprint, a 46.6% reduction in occult carbon, and a 20.9% reduction in operational carbon. The results indicate that the synergistic effect of low-carbon material application and passive energy-saving design is key to achieving deep decarbonization in the renovation of existing buildings in frigid regions, providing a replicable technical path for similar projects.