Similar efforts are afoot in northeastern U.S. states and in Europe, says Mike Henchen, electrification manager for the Rocky Mountain Institute (RMI), a Colorado-based sustainability think tank. He cites the Netherlands as a frontrunner. A plan currently making its way through parliament maps out a phased, community-by-community decommissioning of the country's gas distribution grids. Some 1.5 million homes would be disconnected by 2030.

Behind these moves are the growing number of jurisdictions setting ambitious goals for greenhouse gas emissions, as well as recent high-profile gas leaks and accidents, says Henchen. California’s climate policy calls for zero net emissions by 2045, and removing natural gas looks like the cheapest way to achieve that in the buildings sector. Heat pumps running on all but the most coal-heavy power grids are already cutting carbon and that benefit will only expand as power systems shift to solar and wind energy. The California Energy Commission’s official energy plan cites, “a growing consensus that building electrification is the most viable and predictable path to zero-emission buildings.”

RMI research published last year found that most all-electric buildings pay for themselves over the long haul, though many cost more to construct—a situation they expect to change as increased use of heat pumps drives down their cost. Seattle-based design firm Mithun says they are finding that building without gas can already be cost-neutral or cheaper to build.

Hilary Noll, a Mithun senior associate in San Francisco, says heat pumps are providing savings for five all-electric multifamily housing projects the firm has underway in the city. She says this is primarily due to federal tax credits for affordable housing tied to energy efficiency targets. Those require the addition of solar water heaters when gas boilers are used, helping trim gas consumption. Without gas, additional savings come from avoided equipment such as gas piping, meters, and combustion venting, as well as simplified fire code compliance. “There's a trickle-down effect,” says Noll, who estimates about $250,000 in savings per project.

Noll says Mithun’s clients favor all-electric design primarily as a response to heightened awareness of climate change. But they also feel they are getting a better building. In most of Mithun’s all-electric projects, these savings are being used to upgrade air filtration systems to protect residents from soot from the region’s increasingly frequent wildfires. Owners also recognize that eliminating gas today will future-proof the structures against expensive retrofits. “When you design for natural gas in a building, you’re designing for obsolescence,” says Noll.

Many California cities plan to ban gas only from new municipal buildings, while pushing private developers to go electric by mandating higher efficiency for gas-equipped buildings. Bartholomy says Los Angeles is following another model pioneered in Vancouver, British Columbia: phasing in limits on carbon emissions that will ratchet down over time.

Whatever model jurisdictions use, Bartholomy says, they will have to stop the installation of new gas equipment—which can last 15-20 years—in all buildings by 2030 to have any hope of meeting their mid-century carbon targets.