BOSTON — Environmental officials from nine states have signed an agreement to accelerate the transition to pollution-free residential buildings by expanding heat pump sales to meet home heating, cooling, and water-heating needs.

The memorandum of understanding (MOU), led by the Northeast States for Coordinated Air Use Management (NESCAUM), was signed by the directors of environmental agencies from California, Colorado, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, and Rhode Island.

Under the MOU, those states have set a shared goal to have heat pumps make up at least 65% of the shipments of residential heating, air-conditioning, and water-heating products by 2030, and 90% by 2040. The states will also collaborate to collect market data, track progress, and develop an action plan within a year to support the widespread electrification of residential buildings.

The MOU builds on a September 2023 commitment from the U.S. Climate Alliance’s member states and territories to quadruple heat pump installations by 2030.

“Heat pumps and building electrification are the future for healthier homes and a thriving green economy,” said Serena McIlwain, secretary of the Maryland Department of the Environment, in a press release from NESCAUM. “This multi-state partnership will help Maryland meet its ambitious climate goals and strengthen a coalition of states for cleaner air and better health outcomes.”

“Buildings are the top contributor to greenhouse gas emissions in New York state, and actions are well under way to significantly reduce the amount and impact of these emissions on the state level,” said Basil Seggos, the New York State Department of Environmental Conservation commissioner. “This new multi-state agreement and the strengthened partnership with participating states will bolster New York state’s ongoing efforts to replace fossil fuel infrastructure and install heat pumps in more homes for the benefit of public health and the environment, while setting an example for other states to follow.”

Buildings are a source of air pollution that comes from the combustion of fossil fuels in furnaces, boilers, and water heaters. According to NESCAUM, fossil-fueled heating equipment across the participating states emits annually over 138,000 tons of smog-forming nitrogen oxides (NO_x) and 6,000 tons of fine particulate matter, causing increased risks of heart attack, asthma events, premature death, and other adverse health outcomes. Buildings also annually emit 173 million metric tons of CO₂ across the participating states, NESCAUM said.

Building electrification can deliver widespread health benefits, particularly in densely populated communities with high levels of air pollution, NESCAUM said.

To pave the way for widespread adoption of heat pumps, the agreement emphasizes collaboration with stakeholders, including manufacturers and HVAC installers.

“To achieve our shared decarbonization goals, we need to send an unmistakable signal to the marketplace that zero-emission homes are the future. This agreement does that,” said Matt Rusteika, director of market transformation at the Building Decarbonization Coalition. “We applaud NESCAUM and state leaders for a commitment that is ambitious, flexible, and pragmatic. We’re looking forward to the exciting work ahead.”

A recent letter from business-focused Ceres, a nonprofit that aims to build a more sustainable economy, united 24 businesses, investors, and building owners and operators in supporting the acceleration of heat pump adoption. Last year, 10 of the nation’s largest manufacturers committed to help California achieve its target of having 6 million heat pumps installed by 2030.

“State policy is critical to accelerating the adoption of building technologies that are good for the climate and good for business. Initiatives that encourage collaboration across state lines to develop best practices are essential to accelerating this transition,” said Alli Gold Roberts, senior director of state policy at Ceres. “Ceres and the companies we work with applaud today’s memorandum of understanding for its detailed, collaborative, and ambitious approach to cut pollution from the building sector.”

States signing the MOU committed to promoting the installation of zero-emissions, grid-interactive technologies in existing state buildings. The states also seek to direct at least 40% of efficiency and electrification investments to benefit low-income households facing high energy burdens, and to communities historically burdened with elevated air pollution levels.

“States taking action on this hidden source of pollution are not only delivering healthier air to breathe and a livable climate for their citizens, but also working to ensure that those most burdened by high energy costs and polluted air are the first to benefit,” said Emily Levin, senior policy advisor at NESCAUM.