Evaluating Trade-Offs Between Embodied Carbon Production and Projected Reductions in Operational Carbon Achieved by Façade Retrofit

Abstract

Strategies for reducing carbon emissions associated with commercial buildings are realized by either tracking emissions that correspond to the production, installation and replacement of building materials or tracking emissions that correspond to the occupied use of the building through utility monitoring.  These approaches are distinguished respectively as considering “embodied” and “operational” carbon.  The focus of this paper is to evaluate the net balance that is achieved when the embodied carbon associated with a specific façade installation is compared with the potential savings in carbon emissions that result from its deployment. This study follows the net energy transfer associated with a given unitized façade unit in different climates in accordance with existing weather records and for various building orientations. Recognition is given to potential improvements in thermal performance achieved by reducing air leakage, improving assembly U-factor and enhancing solar control.  The results are evaluated in the context of existing environmental product declarations for the replacement façade and fuel sources corresponding to space conditioning with the goal of determining under what circumstances façade retrofit provides a viable path to reducing emissions.