Heat pumps in Maine give lowest-cost heat, per state energy office

Heat pumps in Maine heated homes and other buildings at a lower per-unit cost compared to furnaces fueled by natural gas, oil, or propane, or electric baseboard heating, according to statewide average data recently reported by the state energy office. 

Maine's state energy office describes the state as having "long been a national outlier for reliance on oil". According to the U.S. Energy Information Administration, "Three-fifths of Maine's households use fuel oil as their primary energy source for home heating, a larger share than any other state." EIA data for 2020 shows that Maine consumed 31 million barrels of petroleum for all uses, with residential heating accounting for 7,155,000 of these barrels at a cost of over $652 million.

Heat pumps provide energy efficient heating and cooling to Maine’s homes and businesses and reduce the state’s high reliance on fossil fuels for heating. State law and Maine's Climate Action Plan establish a goal for the installation of 100,000 new heat pumps by 2025, with 15,000 new heat pumps being provided to income-eligible households. 

Efficiency Maine Trust, the state's quasi-governmental energy efficiency organization, offers rebates for heat pump installations for residential, low-income, and commercial customers. According to Efficiency Maine Trust, "Tens of thousands of heat pumps have been installed in homes and businesses across Maine. They are the most popular heating system across all of Efficiency Maine’s rebates because they offer highly efficient heating, air conditioning, and dehumidification."

A legislative resolve enacted in 2022 directed the Governor's Energy Office to monitor, in coordination with the Office of the Public Advocate and the Public Utilities Commission, factors that directly affect energy supply and costs in the service territory of the northern Maine independent system administrator and in other rural or geographically isolated communities in the State, including, but not limited to, electric grid reliability, availability and costs of electric generation resources, electricity rates and heating fuel supplies and costs.

The Governor's Energy Office released a report in February 2023 addressing the resolve. Regarding heat pumps, the report notes:

Heat pumps provide energy efficient heating and cooling to Maine’s homes and businesses in addition to decreasing the state’s high reliance on fossil fuels for heating. The benefits of heat pump adoption and weatherization not only include lower prices as compared to other common heating systems (which in Maine are predominately delivered fuel), but also climate benefits including reduced greenhouse gas emissions and increased resilience to fossil fuel price swings. 

The report includes a graph presenting a price comparison of common heating systems in Maine, from 2019 through 2021, using statewide average data. The graph shows that heat pumps were the lowest-cost source of heat over the time period, relative to other typical heating systems such as furnaces fueled by natural gas, oil, or propane, or electric baseboard heating:

In addition, Maine utility Central Maine Power Company has offered a "Seasonal Heat Pump Rate" pilot program limited to the first 5,000 participants. The pilot rate differs from the utility's standard tariffed rates, but has potential to provide significant savings to heat pump users whose usage characteristics align with the rate's incentives.