HVAC Services

The Maine Governor's Energy Office surveys home heating fuel dealers across the state and publishes statewide average prices. As of its September 21, 2026 report, No. 2 heating oil averaged $6.02 per gallon and propane averaged $3.23 per gallon (30-day cash price, accounts using 900 or more gallons a year). The U.S. Energy Information Administration (EIA) puts Maine's residential natural gas price at $31.62 per thousand cubic feet as of June 2026, and the average Maine residential electric rate at 19.66 cents per kWh for 2024, the most recent full year on record.

None of those numbers mean much on their own, because a gallon of oil, a therm of gas, and a kilowatt-hour of electricity don't hold the same amount of heat. The EIA's standard conversion factors are 138,500 Btu per gallon of heating oil, 91,452 Btu per gallon of propane, 100,000 Btu per therm of natural gas (about 1.037 million Btu per thousand cubic feet), and 3,412 Btu per kWh of electricity. Dividing price by heat content, then dividing again by the equipment's efficiency, gives a cost per million Btu actually delivered as heat — the only fair way to compare fuels against each other.

Four different ratings show up on heating and cooling equipment, and they aren't interchangeable — each measures a different kind of system, under different test conditions.

AFUE (Annual Fuel Utilization Efficiency) applies to furnaces and boilers that burn fuel. It's the percentage of the fuel's heat content that ends up as usable heat over a full heating season, after chimney and cycling losses. SEER2 and HSPF2 are the current Department of Energy test-procedure versions of the older SEER and HSPF ratings for air conditioners and heat pumps; the 2023 rule behind the '2' raised the external duct static pressure used during testing to better match real installations, so a unit's SEER2 or HSPF2 number is typically a bit lower than the same equipment would have scored under the old test — it isn't a weaker system, just a more realistic one. SEER2 rates cooling efficiency over a season; HSPF2 rates a heat pump's heating efficiency over a season. COP (coefficient of performance) is the most basic of the four: at one specific outdoor temperature, it's simply the heat delivered divided by the electrical energy used to deliver it. A COP of 3 means three units of heat out for every one unit of electricity in. ENERGY STAR's cold-climate heat pump criteria require a COP of at least 1.75 at 5°F, which is the standard's way of making sure a unit still beats plain electric resistance heat even on a cold Maine morning.

A hybrid or dual-fuel setup pairs a heat pump with the oil, propane, or gas system already in the house instead of replacing it outright. The heat pump handles heating and cooling most of the year, since it's the cheapest fuel per MMBtu delivered down to fairly low outdoor temperatures. The existing boiler or furnace stays in place as backup for the coldest stretches, when a heat pump's output and efficiency both drop, or as a backup during a power outage if the furnace can run on a generator circuit.

Cold-climate heat pumps built to NEEP's specification are tested with any supplemental electric-resistance heating elements factored into the rating for the coldest conditions, but a paired boiler or furnace is typically a more efficient and cheaper backup than a heat pump's own built-in resistance strips. Efficiency Maine's guidance on pairing systems is specific on one point: if a heat pump and a second heating system share a space, install them so their thermostats don't work against each other — one system's call for heat shouldn't be blocked or overridden by the other's setpoint. In practice that means either a control strategy that hands off between the two systems at a set outdoor temperature, or clearly separated zones so each system only ever answers to its own thermostat.