Leveraging Existing Buildings

In this critical decade for climate action, the existing built environment is a key asset to achieving substantial, near-term carbon reductions. Leveraging the buildings we already have avoids embodied emissions from new construction, reduces operational emissions from existing buildings, and provides social and economic co-benefits.

Reusing our existing building stock can help us avoid significant environmentally-costly new emissions, while also providing opportunities to reduce building operating emissions through energy upgrades. It’s estimated that reusing and retrofitting existing buildings can save between 50-75% of the embodied carbon that would be expended by constructing new similar buildings. This is particularly relevant in the global north, where we have a lot of existing buildings available to reuse as well as a significant number of underutilized buildings. Reusing these buildings reduces the need for new construction and future embodied carbon emissions and improving the operational performance of our current building stock lowers its current operating emissions.

The benefits of reusing and improving existing buildings doesn’t end with reduced carbon emissions. The built environment consumes vast amounts of natural resources that come with significant environmental impacts. Reusing and improving buildings requires far fewer resources than new construction. Building reuse also supports and revitalizes existing neighborhoods, and can create local jobs, strengthen community control, build financial equity, and increase neighborhood resilience. Investment in communities that have been subjected to historic discrimination and economic “redlining” has the potential to bring sustainable and equitable climate solutions that also have meaningful economic outcomes for the most impacted communities. To make this potential a reality, decisions must be made by, and benefits accrued to, those impacted or affected by the improvements.

In most cases, the greenest building is the one that already exists, but that wisdom has not been proven with comprehensive data. This means that the carbon benefits of reusing existing buildings are rarely incorporated in climate action plans, carbon tracking, or design decision-making, a critical missed opportunity for the preservation, planning, design, and policymaking communities to quantify their impact potential and make the strongest case for building reuse. The Carbon Avoided: Retrofit Estimator (CARE) Tool provides decision-makers with this capability, by offering high-level total carbon projections for reusing and upgrading existing buildings compared to replacing them with new construction.

Meet the Research Team