Federal courts have upheld local building electrification policies, rejecting federal preemption arguments that had previously challenged such rules. The decisions signal a regulatory shift that could accelerate decarbonization across the U.S. built environment. The rulings come after the 2023 9th Circuit struck down Berkeley's ban on gas hookups, a setback for local governments. Since then, 13 lawsuits have been filed across states, targeting rules that require all-electric new buildings or set zero-emissions appliance standards. In all six post-Berkeley cases that reached federal courts, judges rejected the EPCA argument and upheld pro-electrification standards. The decisions were supported by a panel of three judges, with dissenting opinions from 11 judges. The rulings also followed victories in Maryland and Washington, D.C., where district courts affirmed local electrification laws. Five of the six cases have been appealed to higher circuits, and five remain pending in district courts. Daniel Carpenter-Gold, senior staff attorney at the Public Health Law Center, noted that "industry has really gone on a spree" as firms like Reichman Jorgensen Lehman & Feldberg and Baker Botts argue the same language in each case. Tim Oberleiton of Earthjustice said the rulings "have sent a clear message: states and local governments can be confident to move forward with decarbonization programs." Judge Paula Xinis of the District of Maryland pointed out that EPCA's requirement that appliances be tested for energy use prior to sale would be impossible if energy use were interpreted at the site of installation. With one-third of U.S. emissions coming from buildings, the court victories reinforce the feasibility of electrification mandates. Energy-drilling companies and rig managers can anticipate increased demand for electric heating and cooling solutions, potentially reshaping supply chains and investment priorities.