Wood Heating Benefits

Here is a scientific model that shows the benefits of heating with wood versus propane. Scott Salveson, director of the National Firewood Association presents his findings.

BTU FUEL INPUT:

One cord of seasoned white oak = 25.7 mmBTU = $250.00

One gallon of propane = 91,600 BTU. 280 gallons x 91,600 = 25.65 mmBTU

280 gallons x $1.65 = $462.00

HEATING A HOME

Comparison of two readily available furnaces show that combustion efficiency is equal for the highest efficiency gas furnaces and wood burners.

KUUMA VAPOR-FIRE 100 Wood Furnace

Forced-air furnace, EPA Phase II rated. Tested combustion efficiency of 97.3%

GOODMAN GMVM970803BN

Forced-air gas furnace, 97% combustion efficiency

(Note that combustion efficiency is different than overall efficiency, which measures heat transfer into the home and is affected by such things as furnace design, HVAC design and installation, etc. Combustion efficiency is used here as it provides the most accurate comparison between fuels).

These units are representative of the highest-efficiency furnaces available to consumers today. While many consumers will opt for less costly, less efficient units when purchasing, the comparative efficiencies remain quite similar.

EPA Phase 1 rated stoves tend to be in the mid-high 80% efficiency range, while the “mid-efficiency” gas furnaces deliver 86-87% efficiency. Therefore, the cost savings benefit remains constant when comparing units of comparable efficiency.

COST COMPARISON

At $250 per cord, oak firewood is 46% less expensive than the same amount of (input) heat than LP gas at $1.65/gallon.

ENVIRONMENTAL CONCERNS

The primary concern with wood fuel is particulate emissions, which as the Kuuma furnace demonstrates, can be largely mitigated with attendant gains in efficiency. The Phase 2 EPA standards don’t go into effect until 2020, and this stove meets them easily.

It should also be noted that the environmental impact of firewood does not include fracking, pipelines, or major corporations. Firewood is often made from waste wood — timber not suitable for lumber or veneer that would otherwise be burned green in a highly-polluting open fire for disposal. (This seems egregious, but less so than leaving than leaving these wood piles to become fire hazards as they dry).

BOTTOM LINE

When furnaces of equal efficiency are compared, firewood is nearly half the cost of propane. With fuel prices expected to rise, the difference will only become more pronounced.

Scott Salveson
Director
National Firewood Association
Cell: 218-506-8334