What does a million BTU of heat cost at your Portland prices?
Oil, propane, and electricity prefilled with the September 8, 2026 Maine fuel survey for Greater Portland and the actual CMP Rate A residential tariff; the gas input stays an editable national placeholder. Your delivery slip and your CMP bill beat any default here.
| Fuel | $ / MMBtu delivered | $ / year | At these inputs |
|---|
Scroll the table sideways for all columns
Local defaults: heating oil and propane are the Maine Department of Energy Resources survey readings for Southeast / Greater Portland, September 8, 2026 (spot cash averages, not quotes; the propane survey basis is 30-day cash/credit at 900+ gallons a year). Electricity is the actual CMP Rate A residential tariff (24.68¢/kWh volumetric) from the Maine PUC table as of July 1, 2026; the EIA Maine average (29.59¢, June 2026, released August 26, 2026) is available in the selector as a dated fallback that blends all utilities and includes fixed charges. Natural gas remains a national heating-season average because no Portland-area tariff was sourced this pass; gas service reaches only part of the metro. Full sourcing: heating cost methodology.
Assumptions behind the math
Energy content per unit (representative EIA conversion factors): heating oil ≈138,500 BTU/gallon, propane ≈91,452 BTU/gallon, natural gas 100,000 BTU/therm (the definition of a therm), electricity 3,412 BTU/kWh. Efficiency defaults are editable planning assumptions, not measurements: oil boiler 80% AFUE, propane furnace 85%, gas furnace 92%. The heat pump seasonal COP bands (2.2–2.6 standard climate, 2.0–2.4 cold climate) are planning assumptions derived from HSPF2 rating bands, not measured seasonal performance for your home. Adjust any of these to match your own equipment's nameplate rating. Full sourcing and limits: heating cost methodology.
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The same calculator with national defaults and a state selector.
A Portland oil home at the current survey price
The prefilled numbers describe one specific, checkable situation: a home heating with oil at the September 8 Greater Portland survey price, considering a cold-climate heat pump at CMP's current Rate A tariff. It is a modeled scenario, not a customer story.
Heating oil at $5.33/gal through an 80% AFUE boiler delivers heat at about $48.10 per MMBtu. A heat pump at CMP's 24.68¢/kWh and a cold-climate seasonal COP of 2.2 delivers the same million BTU for about $32.88. For a home using 80 MMBtu of heat a year (roughly 720 gallons of oil at that efficiency), that gap is about $1,200 per year in the heat pump's favor, before installation cost.
At these inputs the heat pump stays ahead of $5.33 oil until electricity reaches about 36¢/kWh, well above CMP Rate A's current 24.68¢ total. That margin is why the comparison usually favors the heat pump against oil in this scenario, and it is still worth running with your own numbers: a discounted pre-buy price, a competitive electricity supplier, or a lower-COP installation all move it.
When the heat pump loses
High electricity prices, a lower seasonal COP, or a cheaper current fuel can flip this comparison. Two cases where the heat pump costs more to run:
Against natural gas, at the illustrative price prefilled here. The $1.46/therm default is a national heating-season average, not a Maine rate; at it, a 92% furnace delivers heat for about $15.87/MMBtu, roughly half the heat pump's $32.88 at CMP's tariff. If you have gas service, your actual tariff decides. Gas mains reach only part of the Portland area, and Efficiency Maine's heat pump rebate requires that the home did not have a gas utility account before the upgrade.
Against cheaper oil at a poor COP. Take the survey's low-end September dealer price ($4.89/gal), an 85% boiler, the EIA state-average electricity rate (29.59¢) and a system that only manages COP 2.0 across the winter: oil delivers at about $41.54/MMBtu and the heat pump at about $43.36. The heat pump costs roughly $1.80 more per MMBtu, or about $145 a year at 80 MMBtu. This page will tell you that when your inputs produce it; the result box above does not hide negative savings.
Operating cost is also only half the decision. Installation is the other half, and Efficiency Maine's rebates land on that side of the ledger. Sequence matters too: sealing and insulating first shrinks how much heat you need to buy at any price. See what order to do a retrofit in and the national installation cost calculator.
Where these defaults come from
Prices on this page have dated public sources you can check; the efficiency defaults are editable planning assumptions. Anything you type yourself is yours, not source-verified.
- Maine PUC: residential electricity rates by utility (actual tariffs as of July 1, 2026) checked 2026-09-09
- CMP: pricing (Rate A delivery and standard-offer supply) checked 2026-09-09
- Maine Department of Energy Resources: heating fuel price survey (September 8, 2026 reading) checked 2026-09-09
- EIA Electric Power Monthly, Table 5.6.A, state residential electricity averages (June 2026, released August 26, 2026) checked 2026-09-09
- Efficiency Maine: residential heat pump rebates checked 2026-09-09
- Efficiency Maine: insulation rebates (completions through September 30, 2026) checked 2026-09-09
- Efficiency Maine: heat pump water heater program checked 2026-09-09
- Maine Labor CWRI: metro area labor force estimates (Portland–South Portland MSA = Cumberland, York, Sagadahoc counties) checked 2026-09-09
- Efficiency Maine: home energy loans checked 2026-09-09
- Maine DOER: home energy rebates (HEAR/HOMES status) checked 2026-09-09
The fuel survey updates weekly through the heating season; planned re-review of these defaults follows that cadence, with the insulation program re-checked around its September 30, 2026 completion-date transition. Methodology and formulas: how the heating cost math works.
Portland heating cost questions
Is a heat pump cheaper to run than oil heat in Portland?
At the September 8, 2026 Maine fuel survey price for Greater Portland ($5.33/gal) and CMP's current Rate A tariff (24.68¢/kWh), a heat pump at a cold-climate seasonal COP of 2.2 delivers heat for about $33 per million BTU against about $48 for an 80% AFUE oil boiler, roughly a $15 per MMBtu advantage. At those oil prices the heat pump stays ahead until electricity reaches about 36¢/kWh, well above CMP Rate A's current total. Your numbers decide: enter your own delivery slip and bill above.
What electricity rate should I use?
The prefilled 24.68¢/kWh is the actual CMP Rate A residential tariff for standard-offer customers: the 2026 standard-offer supply price (12.721¢) plus volumetric delivery (11.959¢), per the Maine PUC table as of July 1, 2026. It excludes the $27.37 monthly service charge, which does not change with heating use for a customer keeping electric service. If you buy supply from a competitive supplier or take a different rate, use the combined supply-plus-delivery price from your own bill. The Maine state-average option in the selector is an EIA fallback (June 2026) that blends all utilities and includes fixed charges.
Does natural gas beat a heat pump in Portland?
At the illustrative gas price prefilled here ($1.46/therm, a national heating-season average, not a Maine rate), gas works out to about $15.87 per million BTU against the heat pump's $32.88 at CMP's tariff. If you have gas service, enter the actual rate from your bill before drawing any conclusion. Two local notes: gas service reaches only part of the Portland area, and Efficiency Maine's heat pump rebate requires that the home did not have a natural gas utility account before the upgrade.
Where do rebates fit into this comparison?
This page compares operating cost only. Efficiency Maine currently offers $1,000 per eligible outdoor heat pump unit (up to $3,000 lifetime per housing unit) for any income level, with higher tiers for income-qualified homes, and that money comes off the installation side, not the fuel side. Confirm current program terms with Efficiency Maine before you schedule work; they changed more than once in 2026.
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