This “Cost Study of the Building Decarbonization Code” analyzes the incremental first cost and life cycle cost of two common building types that follow the code language in NBI’s Building Decarbonization Code. The study, which was supported by the Natural Resources Defense Council (NRDC), analyzes first costs for both all-electric and mixed-fuel paths for single-family and medium office prototypes. It also includes life cycle cost analysis for the single-family scenario. Ultimately, the cost study found that all-electric homes achieve construction savings and mixed-fuel buildings households are only nominally more expensive. It also found marginal additional first costs for property owners of the all-electric medium office building prototype, with most of those attributed to electric vehicle charging infrastructure. Additionally, researchers determined that life cycle cost analysis (LCCA) for the single-family prototypes produced both economic and societal benefits. Researchers used cost data from New York State, a relatively expensive market, in colder Climate Zone 5A.