Green building has become an increasingly important piece of the American economy. Two cases from the past five years addressed this burgeoning field: Air Conditioning, Heating and Refrigeration Institute v. City of Albuquerque and Building Industry Association of Washington v. Washington State Building Code Council. As a result of these decisions, legislators would be wise to explicitly evidence their desires when updating or enacting local buildings codes to guard against the potential for severability in the event that the federal Energy Policy and Conservation Act preempts part of the code. So long as they do so, legislators should be able to include both performance- and prescriptive-based paths for compliance. If the state or municipality must choose a single path to compliance, however, it would be most beneficial to emphasize performance-based paths because a credit-based system provides a builder with more flexibility, which will benefit both the project and the environment.