Examining the Collective Impact of Greenhouse Gas Emissions (GHG) on Retrofits of Single-family Homes

The study addresses the pressing issue of reducing carbon emissions in the United States, where buildings account for a significant 40% of greenhouse emissions. While new constructions are gradually becoming more energy-efficient due to stricter building codes, existing buildings, particularly single-family homes built before 1980, continue to contribute significantly to energy consumption and carbon emissions. Currently, retrofits are evaluated and ranked based solely on their potential for energy savings, which does not always translate into a proportional reduction in carbon emissions. 

To overcome this limitation, the study focuses on retrofits for single-family homes in Pittsburgh and Philadelphia, utilizing the Home Energy Saver online tool and Life Cycle Assessment to prioritize retrofits based on their energy savings and carbon emission reduction. The researchers generated a set of 14 retrofits using the US Department of Energy's Home Energy Saver online tool, further categorizing them into shallow, deep, and electric retrofits. This categorization enables a detailed analysis and comparison of their effectiveness in reducing carbon emissions. 

The study's findings reveal valuable insights into the performance of retrofits in Pittsburgh's carbon-intensive grid and Philadelphia. In Pittsburgh, where the grid heavily relies on carbon-intensive energy sources, envelope retrofits rank better than electrification upgrades. This suggests that improving the building envelope's insulation and sealing, such as upgrading windows and insulation, can lead to more significant reductions in carbon emissions. Conversely, in Philadelphia, where the grid utilizes a mix of energy sources with relatively lower carbon intensity, electrification upgrades show a slightly better ranking. This indicates that transitioning to electric heating and appliances can be more effective in reducing carbon emissions in Philadelphia's context. 

Looking ahead, the study envisions an extensive future scope to explore additional dimensions of retrofit implementation. The researchers plan to evaluate strategies to incentivize retrofits for financially burdened single-family homeowners who may face challenges in decision-making. By addressing these barriers, the study aims to promote broader adoption of retrofits and contribute to substantial carbon emissions reductions in the residential building sector.