A federal judge has dismissed a lawsuit by industry groups seeking to overturn Denver’s restrictions on certain natural gas appliances in new commercial and multifamily buildings.

Chief U.S. District Judge Philip A. Brimmer on Aug. 7 granted motions to dismiss filed by the city and intervenor Sierra Club in Restaurant Law Center et al. v. City and County of Denver. The ruling dismissed the complaint with prejudice, meaning the plaintiffs cannot refile the same claims.

The plaintiffs — Restaurant Law Center, National Association of Home Builders of the United States, Colorado Restaurant Association, Home Builders Association of Metropolitan Denver, American Hotel & Lodging Association, National Apartment Association and National Propane Gas Association — argued that Denver Energy Code provisions restricting fossil-fuel and electric-resistance space heating and water heating appliances are preempted by the federal Energy Policy and Conservation Act.

Judge Brimmer rejected the preemption claim. He held that the federal law’s definition of “energy use” refers to a standardized measure set by federal test procedures before a product reaches consumers. Local rules limiting where certain appliances may be installed do not regulate that metric, the court found.

The decision followed a June 2026 Second Circuit ruling that rejected a broader interpretation of the same federal statute. That appellate decision upheld New York State and New York City limits on fossil-fuel appliances in new construction. It conflicted with a 2024 Ninth Circuit decision that struck down a Berkeley, California, ban on natural gas piping in new buildings.

The circuit split means the same federal statute is applied differently depending on geography. Courts in the Second Circuit and most district courts outside the Ninth Circuit have held that local governments may restrict gas appliances in new construction without violating federal preemption.

The Ninth Circuit’s broader reading continues to constrain similar measures in Western states under its jurisdiction. By aligning with the Second Circuit, the Denver ruling places Colorado among jurisdictions that have preserved local authority over building electrification requirements.

The Denver case targeted direct appliance restrictions in the city’s Energy Code for new construction. A separate lawsuit remains pending. Colorado Apartment Association et al. v. Ryan challenges Colorado’s Regulation 28 and Denver’s Energize Denver building performance standards, which set energy-use and greenhouse-gas intensity targets for existing large buildings.

That case, filed earlier in 2024 against both state and city officials, is before a different judge after an amended complaint cured earlier standing problems.

The August dismissal provides a final local ruling that Denver’s 2023 Energy Code standards are not preempted by federal law.