The revised energy code requires heat pumps to heat interiors and water, instead of fossil fuel, electric space heaters or electric resistance water heaters. The code change, which will take effect in the second half of next year, does include some exceptions for supplemental heating.

Jonny Kocher, a senior associate at the Rocky Mountain Institute, along with other environmentalists, support the action. In a letter to the council ahead of the vote, RMI wrote that electrifying buildings would significantly reduce carbon emissions in Washington. An RMI analysis shows that implementing the changes in this code cycle will reduce about 8.8 million tons of carbon dioxide equivalent emissions by 2050, due to avoided natural gas use.

In contrast, Tim Attebery, southern district manager for AGC of Washington, wrote in a letter to the council that the contractor group “has grave concerns” that the move to replace natural gas heating with electricity could increase demand to the point of pushing up costs and increasing the risk of electricity shortages, particularly during peak demand. He also expressed worry that the switch could cause some developers to cancel project plans, reduce the scope of construction or move investments to other states.

“All three options are job killers for construction workers and hurt the economic development we need in rural, suburban and urban communities,” Attebery wrote.

In another letter dated prior to the vote, attorneys representing the Mechanical Contractors Association of Western Washington and the Plumbing Heating Cooling Contractors Association questioned the council’s authority to make a change effectively banning natural gas and threatened legal action if the council approved the code change. 

The energy sector has also voiced opposition to the change. The Northwest Gas Association, which represents four distributors and two interstate pipelines, said they instead support the state’s 2021 Climate Commitment Act, which included a compliance path and pointed to research from the NW Energy Efficiency Alliance, which includes gas and other utility companies. The research projects the 70% reduction goal can be met using existing natural gas technologies. 

The move is aimed at bolstering Washington’s Commercial Clean Buildings Performance Standard. State law requires Washington’s energy code to achieve, by 2031, a 70% reduction in annual net energy consumption, compared to the 2006 code, in all residential and nonresidential construction permitted under the state energy code.

More than 80 current and former elected officials from county, municipal and other local governments signed a letter calling on the council to adopt the heat pump requirements. Moving buildings off fossil fuels represents “the least-cost strategy” to decarbonize them, they claimed, citing the 2021 Washington State Energy Strategy. According to the letter, at least a dozen Washington cities have implemented or are in the process of developing climate action plans to curb greenhouse gas emissions. 

A growing number of cities across the U.S. have enacted similar building requirements in the past few years, though more often by banning natural gas in new or retrofitted buildings than by requiring heat pumps, specifically following Berkeley, Calif. In 2019. Officials passed a New York City natural gas ban in December that will phase in over the next few years. 

Heat pumps differ from traditional heating equipment like furnaces by using electricity to move heat from a cool space to a warm space, allowing them to bring heat inside during the cool season and move heat outside during the warm season. According to the International Energy Agency, the number of heat pumps installed in North America has risen from 23 million in 2010 to 40.1 million in 2020. Globally, the group says having 600 million heat pumps installed by 2030 will help achieve net-zero emissions by 2050.