Hardwood vs Softwood Firewood Compared Using USU Data
"Hardwood" and "softwood" are botanical terms, not measures of how hard the wood is. Softwoods come from conifers such as pine, spruce, fir and cedar. Hardwoods come from broadleaf trees such as oak, maple and ash. This page sorts the species in the Utah State University (USU) Extension firewood table into those two groups, a split made for this page rather than by USU, and compares what the table says about each.
Heat and weight
For the 44 species in USU Table 1 that have a heat figure: 31 are hardwoods and 13 are softwoods.
| Hardwoods (31) | Softwoods (13) | |
|---|---|---|
| Average heat per cord | 22.0 million BTU | 18.5 million BTU |
| Median heat per cord | 20.9 million BTU | 18.2 million BTU |
| Lowest | Basswood and buckeye, 13.8 | Eastern redcedar, 13.0 |
| Highest | Osage-orange, 32.9 | Pinyon, 27.1 |
| Average dry weight per cord | 3,126 lb (29 species with a weight) | 2,573 lb (13 species) |
On average a softwood cord holds about 84% of the heat of a hardwood cord (18.5 ÷ 22.0), and weighs less. The averages hide a big overlap, though.
The groups overlap
- Four softwoods beat the hardwood median of 20.9: pinyon (27.1), Rocky Mountain juniper (21.8), larch (21.8) and lodgepole pine (21.1).
- Pinyon at 27.1 holds more heat per cord than red oak (24.6) or white ash (24.2).
- Some hardwoods are lightweight in heat. Cottonwood (15.8) holds about the same as white pine (15.9), and basswood and buckeye (13.8) hold less than every softwood except eastern redcedar (13.0).
So "hardwood" does not guarantee more heat. Look up the species in the BTU chart instead of going by the group.
Sparks and coals
USU's table also rates how many sparks a wood throws and how good its coals are. Counting the groups (the full table has 33 hardwoods and 13 softwoods):
| Rating | Hardwoods | Softwoods |
|---|---|---|
| Sparks: Few | 27 of 33 | 3 of 13 |
| Sparks: Many | 3 of 33 (mulberry, osage-orange, poplar) | 9 of 13 |
| Coals: Excellent or Good | 25 of 33 | 0 of 13 |
| Coals: Poor | 4 of 33 | 8 of 13 |
USU says sparks matter most for open fireplaces, where embers can leave the fire, and that good coals suit a wood stove because they hold a fire overnight. The remaining ratings are in between or not rated.
The 13 softwoods
Sorted by heat, with dry weight, sparks and coals from USU:
| Softwood | Million BTU per cord | Dry weight (lb) | Sparks | Coals |
|---|---|---|---|---|
| Pinyon | 27.1 | 3,000 | Many | not rated |
| Juniper, Rocky Mountain | 21.8 | 3,150 | Many | Poor |
| Larch (Tamarack) | 21.8 | 3,330 | Many | Fair |
| Pine, Lodgepole | 21.1 | 2,610 | Many | Fair |
| Douglas-fir | 20.7 | 2,970 | Few | Fair |
| Hemlock | 19.3 | 2,700 | Many | Poor |
| Redcedar, Western | 18.2 | 2,632 | Many | Poor |
| Pine, Ponderosa | 16.2 | 2,336 | Many | Fair |
| Pine, White | 15.9 | 2,250 | Moderate | Poor |
| Spruce | 15.5 | 2,240 | Many | Poor |
| Spruce, Engelmann | 15.0 | 2,070 | Few | Poor |
| Fir, White | 14.6 | 2,104 | Few | Poor |
| Redcedar, Eastern | 13.0 | 2,060 | Many | Poor |
Only Douglas-fir, Engelmann spruce and white fir are rated Few for sparks, and they sit in the middle or bottom for heat. Pinyon has the most heat but throws Many sparks.
Weight and cost
A softwood cord is lighter, so it is easier to haul, but it also holds less heat, so a cord should cost less to be an equal buy. White pine, for example, holds 15.9 against 24.6 for red oak, so it would need to cost about 65% as much. Use the price converter to compare quotes in cost per million BTU. Whatever the species, the standard is wood at 20% moisture or less (U.S. Department of Energy), covered in the seasoning guide.
Sources
- Utah State University Extension, Wood Heating, Table 1: heat, weight, sparks and coals by species. The hardwood and softwood grouping and the averages are this site's own calculations from that table.
- U.S. Department of Energy, Wood and Pellet Heating: 20% moisture standard.