1 Your prices and system

From your bills, in therms of gas, gallons of propane or oil, or kWh of electricity for heating.
$per therm
US average for 2025 was about $1.48 per therm (EIA). Leave blank to skip.
$per gallon
US average $2.83 for the week of Nov 9, 2026, before taxes (EIA).
$per gallon
US average $5.92 for the week of Nov 9, 2026, before taxes (EIA).
cents per kWh
US residential average 18.16¢ in August 2026 (EIA).
%
On the furnace label. ENERGY STAR gas furnaces are 95% or higher in the South, 97% in the North.
%
ENERGY STAR oil furnaces are 87% or higher.
On the yellow EnergyGuide label. ENERGY STAR split systems are 7.8 or higher.

2 Cost of heat

Cheapest heat
Natural gas furnace
$15.58 per million Btu delivered
Heat you used
66.5 million Btu
delivered last winter by your natural gas furnace
SystemPriceEfficiencyPer million BtuLast winter's heat
Natural gas furnace (yours)$1.48 per therm95%$15.58$1,036
Electric heat pump18.16¢ per kWhCOP 2.29$23.28$1,548
Propane furnace$2.83 per gallon95%$32.57$2,166
Heating oil furnace$5.92 per gallon87%$49.13$3,267
Electric baseboard or furnace18.16¢ per kWh100%$53.22$3,539

Ten therms of natural gas hold one million Btu; a 95% furnace delivers 950,000 Btu of it. Prices change with the season and the region, so enter the prices from your own bills for the most accurate answer. The heat pump figure uses its seasonal rating; in very cold weather it delivers less heat per kWh.

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