Lawsuit targets Denver’s restrictions on use of natural gas in buildings

A group of national and Colorado organizations is suing to overturn Denver building codes intended to address the effects of climate change by limiting the use of natural gas in buildings.

The lawsuit filed Wednesday in U.S. District Court in Denver takes aim at a city ordinance that prohibits natural gas furnaces and water heaters in new commercial and multifamily buildings.

Also targeted is an ordinance that takes effect in 2025 and requires installation of electric systems when gas furnaces and water heaters are replaced in existing buildings and when if it is cost-effective.

Other communities in Colorado and in other states have enacted similar bans as they push to electrify buildings to reduce the effects of climate change and improve air quality. Denver’s climate office estimates that buildings and homes produce nearly two-thirds of the city’s heat-trapping greenhouse gasses causing climate change.

A website by a coalition that tracks policies to reduce emissions associated with buildings lists 135 local governments and six states with laws on the books. In 2022, Crested Butte approved requiring electric heating and water heaters in new residential and commercial buildings.

However, a 2023 federal appeals court decision that prompted the city of Berkeley, Calif., to scrap its ban on natural gas hookups for new homes is raising questions about restrictions on natural gas equipment. The court said the rule violated a federal law that authorizes the Department of Energy to set energy efficiency standards for appliances.

The challenge to Denver’s ordinances claims that they also violate the federal Energy Policy and Conservation Act, which includes energy conservation standards for consumer products. In addition, Denver’s requirements will drive up business costs, jeopardize jobs and make housing, energy, lodging and food service more expensive, the lawsuit said.

Similar claims were made in a lawsuit filed in April by the Colorado Apartment Association, the Apartment Association of Metro Denver, Colorado Hotel and Lodging Association and NAIOP, a commercial real estate association. The complaint also objects to state building codes to electrify buildings.

A spokesperson for Denver’s Office of Climate Action, Sustainability and Resiliency said the agency doesn’t comment on litigation.