THE CARE TOOL

The CARE (Carbon Avoided: Retrofit Estimator) Tool is used for calculating and comparing the embodied, operating and avoided carbon impacts and benefits of reusing and upgrading existing buildings or replacing them with new construction.

Background

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.

What does the tool do?

The CARE Tool estimates the operational and embodied carbon emissions associated with reusing and upgrading an existing building or replacing it with new construction.

Who is the tool for?

The CARE Tool can be used by policymakers, planners, building owners, developers, heritage building officers, architects, and others who are interested in a pre- or early-design, high-level assessment of the total carbon emissions of building reuse versus replacement.

Receive updates about CARE Tool development:

If you would like to receive an announcement when the free online tool is available to the public, please sign up to receive updates above.

How does the tool work?

Users provide information in four categories: 

  1. General project information such as location and building use type(s).
  2. Information about the renovation using drop-down menus to describe scope, such as percentage of structure upgraded or interior finishes retained; information about building additions constructed as part of a reuse scenario; and energy and emissions targets and projections for the renovation.  
  3. New building information based on typical construction typologies, and energy and emissions targets and projections for the new building.
  4. Special conditions such as poor soil or seismic zone location.

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.

BE A CATALYST FOR PROGRESS

How is the tool funded?

The CARE Tool is currently being funded by a 2020 ONEder Grant and 2021 Moe Family Fund Grant through the National Trust for Historic Preservation via the Boston Preservation Alliance. 

The CARE team is currently seeking additional support for tool development.

Current development plans include:

  • Validating and refining backend data assumptions
  • Converting the excel tool to a free, user-friendly online tool

Future development plans include:

  • The integration of projected future electricity grid changes into emissions assumptions
  • The creation of feature for comparing multiple reuse and new construction scenarios for a single project
  • The development of a CARE for Portfolios feature
  • The expansion of the tool for easier and more accurate international use