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Q. A customer asked me how to compare the cost of different heating fuels (natural gas, propane, oil, and electricity). Can you provide a chart with this information?

A.Energy and sustainable design consultant Andy Shapiro responds: The tables at right are based on seasonal delivered efficiency. Because it accounts for equipment, pipe, duct, and other losses, seasonal heating efficiency is lower (by about 5% to 15%) than the listed efficiency of the equipment (the AFUE, or annual fuel utilization efficiency) or the steady-state tested efficiency.

Oil
Cost per million Btus, delivered
Cost per gallon50% efficiency70% efficiency85% efficiency
$0.80 $11.76 $8.40 $6.92
$1.00 $14.71 $10.50 $8.65
$1.25 $18.38 $13.13 $10.81
$1.50 $22.06 $15.76 $12.98

Efficiencies for oil equipment range from 50% for lower-efficiency water heaters to 85% for the best oil furnaces and boilers. Older boilers typically have seasonal efficiencies around 70%.

Propane
Cost per million Btus, delivered
Cost per gallon50% efficiency75% efficiency 90% efficiency
$1.00 $21.39 $14.26 $11.88
$1.25 $26.74 $17.83 $14.85
$1.50 32.09 $21.39 $17.83
$2.00 $42.78 $28.52 $23.77
$3.00 $64.18 $42.78 $35.66
>Natural gas
Cost per million Btus, delivered
Cost per ccf or therm50% efficiency75% efficiency90% efficiency
$0.70 $14.00 $9.33 $7.78
$0.85 $17.00 $11.33 $9.44
$1.00 $20.00 $13.33 $11.11

Efficiencies for propane and natural gas equipment range from 50% for lower-efficiency water heaters, to 80-85% for typical new furnaces and boilers, and 90% for condensing furnaces and boilers.

Electricity
Cost per mllion Btus, delivered
Cost/kWh90% efficiency100% efficiency200% efficiency300% efficiency
$0.05 $16.28 $14.65 $7.32 $4.88
$0.08 $26.04 $23.44 $11.72 $7.81
$0.11 $35.81 $32.23 $16.11 $10.74
$0.15 $48.83 $43.95 $21.97 $14.65

Efficiencies for electric equipment range from 90% for older water heaters and 95% for new water heaters to 100% for resistance heating, 200% for typical heat pumps, and 300% for the highest-efficiency ground-source heat pumps, depending on particular equipment and climate.