Synopsis

Trade groups for landlords, hotels, and developers sued the City and County of Denver and the State of Colorado, arguing that state and local rules to reduce building energy use and emissions are preempted by the federal Energy Policy and Conservation Act (EPCA). 

Why It Matters for Public Health

Climate change is widely accepted as the greatest threat to global public health, and any policy that reduces the extent of climate change helps protect health. Further, actions that reduce energy use and greenhouse-gas emissions also reduce indoor and local air pollution. For example, recent studies show that gas stoves create harmful levels of nitrogen dioxide and benzene inside the home, comparable to secondhand smoke. At the same time, efficiency measures such as improving a building’s sealing and ventilation systems can prevent mold or pest infestations and improve temperature control.

The policies challenged in this case, called “Building Performance Standards,” are particularly important for climate and health. Building performance standards cap certain large buildings’ energy use (or, at the owner’s option, greenhouse-gas emissions), then reduce that cap over a period of years.  Building performance standards are one of the few types of green-building regulation that apply to buildings as they are now, rather than being limited to new buildings, renovations, or appliance replacements. As a result, they are crucial to addressing the quality and emissions of existing buildings.

Background

EPCA is a federal law that, among other things, creates energy-efficiency standards for certain appliances and allows the U.S. Department of Energy to amend those standards and create others. EPCA also preempts state and local regulations “concerning the energy efficiency, energy use, or water use” of an appliance that is covered by EPCA. Generally speaking, EPCA preemption has been considered to preclude only state or local regulations that try to set energy efficiency standards for EPCA-covered appliances. However, in California Restaurant Association v. City of Berkeley, the Ninth Circuit held that EPCA also preempts certain kinds of regulations that are not efficiency standards, but which have the effect of preventing the use of EPCA-covered appliances.

The plaintiffs in this case allege that the Denver and Colorado regulations are preempted by the EPCA as interpreted by the Ninth Circuit. (Importantly, Colorado is not in the Ninth Circuit, and therefore the federal court that will hear this case is not required to follow California Restaurant Association.) Specifically, they have three related arguments:

• That the Denver and Colorado regulations “directly regulate[]” EPCA-covered appliances by placing a cap on the energy use or carbon emissions of certain buildings.
• That EPCA requires the Denver and Colorado regulations to “maintain[] neutrality on energy sources,” which the regulations do not do because of their option for reducing carbon emissions instead of building energy use.
• That it will be impossible to comply with the building performance standards without replacing their gas appliances, implying that the regulations effectively prevent the use of some gas appliances in some buildings.

Litigation Status (Open)

The plaintiffs filed their complaint on April 22, 2024. On August 19, the Coalition for Community Solar Access, Colorado Solar and Storage Association, Natural Resources Defense Council, and Sierra Club became intervenors in the case, supporting Colorado and Denver.

On March 28, 2025, the District of Colorado dismissed the plaintiffs’ case without prejudice for failure to allege standing. The plaintiffs had argued that the state and local regulations would “effectively” require them or their members to install appliances that were more efficient than federal efficiency standards mandate. The court found that, because there are several different ways to comply with these standards, the plaintiffs need to explain specifically how they would be forced to use higher-efficiency appliances. The plaintiffs requested leave to refile an amended complaint with more specific allegations.

The court permitted the complaint to be refiled on August 21, finding that the plaintiffs had addressed the original standing issues and that the case could be considered as a challenge to the regulations as they are applied to the plaintiffs’ buildings. The court also noted that it “does have concerns with” the lack of specificity in the complaint regarding which appliances would need to exceed federal standards in order to comply with the challenged regulations.

The plaintiffs filed their amended complaint on June 10, 2025. The defendants and intervenors moved to dismiss the new complaint on October 3, and briefing on the motion finished on November 26, 2025. The Air-Conditioning, Heating, and Refrigeration Institute filed an amicus brief in support of the plaintiffs on November 12. The court can now either rule on the motion or conduct an oral argument.

On June 18, the US Department of Justice submitted a notice of potential participation, saying that it may file a brief if the case continues through a motion to discuss.