AbstractBuildings are the single largest user of energy in the US and can account for 50%–75% of carbon emissions in large cities. Adopting effective regulations for encouraging more energy-efficient buildings is therefore paramount. Besides the voluntary programs, the regulatory bodies (e.g. municipalities) have different mandatory programs to motivate energy efficiency in new and existing buildings. While building energy codes and auditing are traditional law instruments, an increasing number of cities across the US have adopted building energy benchmarking laws in recent years. This study evaluates the building energy regulations and laws in seven US cities. In particular, it focuses on three major aspects of the building energy laws for each city: (1) scope and compliance, (2) implementation and enforcement, and (3) contribution to the emission reduction. The results show that although energy codes are necessary to establish minimum requirements for new buildings, adopting mandatory benchmarking and transparency laws can significantly reduce energy use. The study concludes with a comparison of adopted energy laws in selected cities and discusses the factors affecting the successful adoption of benchmarking policies such as compliance rate and training of building owners. The results of this study can raise the awareness of policymakers for implementing more effective building energy regulations.