As efforts to decarbonize accelerate, the design community is working to measure and reduce embodied carbon across the built environment. The façade, as both the architectural signature and separation point between indoor and outdoor climates, plays a disproportionate role in a building’s carbon footprint. Industry estimates suggest façades account for 15–20% of a building’s total embodied carbon — yet, no consistent, streamlined methodology exists to evaluate this impact during the design process. Current databases are proprietary systems, inconsistently formatted, and restricted by legal limitations on use. Façade design often combines custom components with distinct carbon footprints, while the assembly of prefabricated or unitized systems adds further embodied carbon complexity. This research sought to address the shortcomings in building envelope design by developing a streamlined, replicable methodology to evaluate typical curtain wall assemblies. Using a system modeled after accessible metrics like “miles per gallon,” the team established relative benchmarks to guide design decisions. The team used internal modeling, analyzed environmental product declarations (EPDs), and collaborated with external partners to develop early frameworks that enable relative comparisons of wall systems, enabling earlier, more effective conversations about carbon impact, when the greatest reductions can be achieved. These results façade carbon discussions while highlighting challenges such as confidentiality, data gaps, and inconsistent metrics.