Massachusetts is the first state in which all the major utilities are offering these savings. The rates — ranging from 4.3 cents to 7.5 cents per kilowatt-hour lower than the standard winter price — could trim from $70 to $140 per month off the average bill, utilities estimate. The lower rate applies to all electricity used by participating homes during the winter months.

Households that received heat-pump rebates from state energy-efficiency program Mass Save since 2019 will be automatically enrolled in the new rate. Residents who installed heat pumps earlier or didn’t work with Mass Save can contact their utility to receive the lower rate.

Massachusetts, like other states with ambitious climate goals and cold winters, has made heat-pump adoption a key part of its decarbonization strategy. Today, more than half the homes in the state use natural-gas heating, and another 25% burn heating oil or propane. More than 90,000 homes installed heat pumps from January 2021 to July 2024, but annual adoption rates will need to double over the next five years if the state is to hit its goal of getting the systems into 500,000 homes between 2020 and 2030.