Renovating an existing structure usually has a much lower carbon footprint than building new because renovations typically reuse most of the carbon intensive parts of the building — the foundation, structure and building envelope. Retrofitting an existing building can also dramatically reduce its operating emissions. Despite this intuitive knowledge, the building industry hasn’t had a simple way to compare all the variables of embodied and operating carbon over different timeframes for reuse and new construction scenarios. Retrofitting an existing building to zero operating emissions will almost always be the lowest carbon option. But what if you can reduce its operational emissions by 50%, or replace it with a new zero operating emissions building? Does it make more sense to retrofit or build new? And how do geography, grid intensity, and the condition of the existing building affect those considerations? The CARE Tool is a simple, easy-to-use tool to answer these questions.
The CARE Tool estimates the operational and embodied carbon emissions associated with reusing and upgrading an existing building or replacing it with new construction.
The CARE Tool can be used by policymakers, planners, building owners, developers, heritage building officers, architects, educators, and others who are interested in a pre- or early-design, high-level assessment of the total carbon emissions of building reuse versus replacement.
Users provide information in four categories:
The CARE Tool then calculates carbon emissions using built-in embodied and operational carbon assumptions. The outputs are visualized as total embodied and operational emissions over a specified timeframe as well as cumulative emissions over time, for three scenarios: the existing building, the renovated building, and the new construction. Results can then be compared to determine the lowest total-carbon approach.
Proposed future additions to the tool include the integration of projected future electricity grid emissions intensity data, the creation of a feature for comparing multiple reuse and new construction scenarios for a single project, the development of a CARE for Portfolios feature, and the expansion of the tool for easier and more accurate international use.
The CARE Tool is currently being funded by grants and donations. See below for a list of current CARE Tool Supporters.
Future development plans include:
