Charlie Kinsella, an installer for Royal River Heat Pumps, checks a hole he drilled in a home in Cumberland on Oct. 11. Ben McCanna/Staff Photographer

A shift toward installing electric heat pumps for the entire house instead of individual rooms is so far paying off with a sharp rise in consumer interest, said the quasi-state agency that oversees energy efficiency programs.

Efficiency Maine Trust gave more rebates for whole-home heat pumps in three months this summer than it did during the previous nine months, Executive Director Michael Stoddard said in an Oct. 30 report. The agency issued 1,814 rebates from July through September compared to 1,805 from October 2023 to June, when its fiscal year ended.

The agency said 563 rebates for whole-home heat pumps were issued in September, the most in a month since the program shifted to whole-home heat pump rebates in September 2023. An average of 201 rebates a month were issued last year; in the first three months of this fiscal year – July, August and September – the monthly average was 604.

Efficiency Maine altered its rebate program in September 2023 and increased the subsidy to help make electricity the primary home heat source and discourage secondary use of oil or gas, which are fossil fuels that contribute to greenhouse gas emissions.

“At the time there were some concerns whether customers would find it desirable or contractors would keep themselves gainfully employed and keep their workforce,” Stoddard said. “In the early months we didn’t know how it would work.”

With another monthly report,  Efficiency Maine has enough information “to see it is cranking,” he said.

The pumps extract heat from outdoor air or from underground and transfer it inside, instead of heating up a coil in a furnace. They also cool interiors by pulling heat from indoors and transferring it to outside or underground.

The Maine Public Utilities Commission said the heat pump technology is the same, but Efficiency Maine has generally shifted to offering incentives only for whole-building installations because it says it’s more cost-effective than heat pumps that supplement other heating systems. Whole-home installations get the most out of heat pumps, according to Efficiency Maine.

Federal and state incentives of up to $10,600 are available. Efficiency Maine provides rebates to low-income households – those eligible for home energy assistance, the Supplemental Nutrition Assistance Program, Temporary Assistance for Needy Families or MaineCare – for 80% of a project’s cost, up to an $8,000 lifetime rebate limit.

Moderate income homeowners, those with an adjusted gross income of up to $70,000 for an individual tax filer or $100,000 for joint filers, are eligible for 60% of a project’s cost, up to a $6,000 lifetime rebate limit.

A rebate of 40% of a project’s cost, up to a $4,000 lifetime limit, is available for households of any income.

A federal tax credit of up to $2,600 is also available.

Thomas Tutor, residential sales team manager at ReVision Energy, which installs solar panels and electric heat pumps, said the number of heat pump installations increased this year over 2023, though he did not have numbers. Most of the projects are whole-home heat pump installations, he said.

“We’re certainly doing more home heat pump systems,” he said. “The project size has increased as more and more people are encouraged to go after the whole house.”

Tutor cautions users to expect their electricity bill to rise. But he said they should remember the cost of the fuel – natural gas, oil, propane – they previously used and are now replacing. “Sometimes people are surprised in the first winter,” he said.

Gov. Janet Mills has made a priority of installing heat pumps in Maine to cut greenhouse gas emissions. Efficiency Maine has spent $119.3 million since 2014, with funding from various sources, including a portion from the federal government. Millions of dollars more are expected from the U.S. Environmental Protection Agency and Department of Energy. MaineHousing, too, has benefited from money from Washington to install electric heat pumps.

It’s unclear if future subsidies might be cut after President-elect Donald Trump takes office in January. He has criticized Biden administration policies advancing zero carbon energy as a “green new scam.”

Stoddard said Efficiency Maine does not have information about the election’s impact on market demand for heat pumps. The increase in demand for heat pumps reported by Efficiency Maine reflects activity in July, August and September.

David Friedman, senior director of federal policy at Rewiring America, which promotes electrification, said it would be difficult, if not impossible, for the Trump administration to claw back federal money in the pipeline for electric heat pumps. And cutting funding for projects in the months ahead “certainly wouldn’t be politically popular,” he said, putting pressure on Congress to protect the programs, he said.

Homeowners in the U.S. used $8 billion in tax credits in 2023 for electrification, energy efficiency and other programs, Friedman said.