Massachusetts Heat Pump vs. Propane: A Spring 2026 Cost Example

Under the spring 2026 inputs below, delivering 10 million Btu costs about $257.73 with a heat pump at COP 3 or $443.34 with a 90%-efficient propane furnace. These are calculated scenarios, not observed household bills or current September quotes.

The propane input is $3.649/gallon, EIA’s Massachusetts residential observation for March 30, 2026. Read the dated EIA series. For electricity, the example uses the April 2026 R1HP winter-season delivery components for Greater Boston, Cambridge and the South Shore plus Eversource’s February–July fixed basic supply price. The adjacent dates are stated explicitly; they are not a forecast for winter 2026–27.

Compare the same useful heat

The historical R1HP delivery lines sum to $0.10752/kWh. Adding basic supply of $0.15629 gives $0.26381/kWh. This includes all listed variable delivery components for that territory, rather than distribution alone.

Using EIA’s sample heat-content conversions, 1 kWh equals 3,412 Btu and propane contains 91,452 Btu per gallon. At an assumed COP of 3, the heat pump needs 10,000,000 ÷ (3 × 3,412) = about 976.94 kWh. Multiplying the unrounded quantity by $0.26381 gives $257.73.

At an assumed 90% furnace efficiency, propane use is 10,000,000 ÷ (91,452 × 0.90) = about 121.50 gallons. At $3.649/gallon, the result is $443.34. Final amounts use unrounded inputs.

When the comparison changes

At these prices and furnace efficiency, the variable-fuel break-even COP is about 1.74. Performance below that point reverses the comparison. A cold-weather backup element, defrost and household operating choices can change the effective COP, so equipment sizing and measured performance matter.

The existing electric account’s $10 customer charge is excluded from incremental heating cost. Propane tank rental, delivery minimums, furnace electricity, taxes, assistance discounts and installation are also outside this comparison. Replace each dated price with the actual account or supplier quote before choosing equipment. A fuel-cost difference alone does not establish installation payback.