The legal challenge, spearheaded by the National Association of Home Builders and Washington Gas, argues that D.C.’s Clean Buildings Act oversteps federal authority. They contend that the city is using building codes to regulate appliances—specifically furnaces and stoves—in a manner prohibited by the Energy Policy and Conservation Act (EPCA). U.S. District Judge Ana Reyes previously upheld the local law, distinguishing between federal control over appliance efficiency and a city’s right to determine building installation standards.

This dispute highlights a deep fracture in federal jurisprudence. While the Ninth Circuit struck down a similar ban in Berkeley, California, last year, the Second Circuit recently ruled in favor of New York’s fossil-fuel restrictions. The D.C. Circuit now sits at the center of this regional divide. Should the panel uphold the city’s 2027 zero-energy mandate, the gas industry faces a patchwork regulatory landscape where the legality of appliance bans rests entirely on geographic jurisdiction.