Thermal Resistivity of Wood
The table below lists representative room-temperature thermal resistivity values for common hardwood and softwood species
at two conditions: ovendry and 12% moisture content (MC). Values are shown in
SI units (K·m·W−1) and, in parentheses, U.S. customary per-inch units
(h·ft2·°F·Btu−1·in−1).
Remember: resistivity is the inverse of thermal conductivity (higher resistivity ⇒ lower heat flow).
|
Species
|
Resistivity
(K·m·W-1 (h·ft2·°F·Btu-1·in-1))
|
| Ovendry |
12% MC |
|
Hardwoods
|
| Ash, black | 8.2 (1.2) | 6.8 (0.98) |
| Ash, white | 7.1 (1.0) | 5.8 (0.84) |
| Aspen, Big tooth | 10 (1.5) | 8.5 (1.2) |
| Aspen, Quaking | 10 (1.5) | 8.6 (1.2) |
| Basswood, American | 11 (1.6) | 9.0 (1.3) |
| Beech, American | 6.6 (0.96) | 5.4 (0.78) |
| Birch, sweet | 6.4 (0.92) | 5.2 (0.76) |
| Birch, yellow | 6.8 (0.98) | 5.6 (0.81) |
| Cherry, black | 8.2 (1.2) | 6.8 (0.98) |
| Chestnut, American | 9.4 (1.4) | 7.8 (1.1) |
| Cottonwood, Black | 12 (1.7) | 9.6 (1.4) |
| Cottonwood, Eastern | 9.8 (1.4) | 8.1 (1.2) |
| Elm, American | 8.1 (1.2) | 6.7 (0.96) |
| Elm, rock | 6.7 (0.97) | 5.5 (0.80) |
| Elm, Slippery | 7.9 (1.1) | 6.5 (0.93) |
| Hackberry | 7.7 (1.1) | 6.4 (0.92) |
| Hickory, pecan | 6.6 (0.95) | 5.4 (0.77) |
| Hickory, mockernut | 5.9 (0.85) | 4.8 (0.69) |
| Hickory, shagbark | 5.9 (0.86) | 4.9 (0.70) |
| Magnolia, southern | 8.4 (1.2) | 6.9 (1.0) |
| Maple, Black | 7.4 (1.1) | 6.1 (0.88) |
| Maple, Red | 7.9 (1.1) | 6.5 (0.93) |
| Maple, Silver | 8.6 (1.2) | 7.1 (1.0) |
| Maple, Sugar | 6.8 (0.98) | 5.6 (0.81) |
| Oak, Northern red | 6.9 (1.0) | 5.7 (0.82) |
| Oak, Southern red | 7.2 (1.0) | 5.9 (0.85) |
| Oak, white | 6.3 (0.91) | 5.2 (0.75) |
| Sweetgum | 8.0 (1.2) | 6.6 (0.95) |
| Tupelo, black | 8.1 (1.2) | 6.7 (0.96) |
| Tupelo, water | 8.2 (1.2) | 6.8 (0.98) |
| Yellow-poplar | 9.3 (1.3) | 7.7 (1.1) |
|
Softwoods
|
| Baldcypress | 9.1 (1.3) | 7.5 (1.1) |
| Cedar Atlantic white | 12 (1.7) | 9.9 (1.4) |
| Cedar Eastern red | 8.9 (1.3) | 7.4 (1.1) |
| Cedar Northern white | 13 (1.8) | 11 (1.5) |
| Cedar Port-Orford | 9.8 (1.4) | 8.1 (1.2) |
| Cedar Western Red | 12 (1.7) | 10 (1.5) |
| Cedar Yellow | 9.3 (1.3) | 7.7 (1.1) |
| Douglas-fir Coast | 8.5 (1.2) | 7.0 (1.0) |
| Douglas Interior north | 8.6 (1.2) | 7.1 (1.0) |
| Douglas Interior west | 8.4 (1.2) | 6.9 (1.0) |
| Fir Balsam | 11 (1.6) | 9.2 (1.3) |
| Fir White | 10 (1.5) | 8.5 (1.2) |
| Hemlock Eastern | 10 (1.4) | 8.3 (1.2) |
| Hemlock Western | 8.9 (1.3) | 7.4 (1.1) |
| Larch, western | 7.9 (1.1) | 6.5 (0.93) |
| Pine Eastern white | 11 (1.6) | 9.2 (1.3) |
| Pine Jack | 9.4 (1.4) | 7.8 (1.1) |
| Pine Loblolly | 8.1 (1.2) | 6.7 (0.96) |
| Pine Lodgepole | 9.8 (1.4) | 8.1 (1.2) |
| Pine Longleaf | 7.2 (1.0) | 5.9 (0.85) |
| Pine Pitch | 8.2 (1.2) | 6.8 (0.98) |
| Pine Ponderosa | 10 (1.4) | 8.3 (1.2) |
| Pine Red | 9.3 (1.3) | 7.7 (1.1) |
| Pine Shortleaf | 8.1 (1.2) | 6.7 (0.96) |
| Pine Slash | 7.3 (1.1) | 6.0 (0.86) |
| Pine Sugar | 11 (1.6) | 9.2 (1.3) |
| Pine Western white | 10 (1.5) | 8.6 (1.2) |
| Redwood Old growth | 10 (1.5) | 8.5 (1.2) |
| Redwood Young growth | 11 (1.6) | 9.2 (1.3) |
| Spruce Black | 9.8 (1.4) | 8.1 (1.2) |
| Spruce Engelmann | 11 (1.6) | 9.2 (1.3) |
Note: Values in this table are approximate and should be used with caution; actual values may vary by as much as 20%.
Moisture content and growth conditions significantly influence thermal properties.
Material Properties of Wood:
Frequently Asked Questions
What is thermal resistivity of wood?
It’s the inverse of thermal conductivity. A higher resistivity means wood is more insulating and resists heat flow.
Which units are used on this page?
SI values are K·m·W−1. U.S. customary values in parentheses are per inch: h·ft2·°F·Btu−1·in−1.
Why list both ovendry and 12% MC?
Because moisture lowers resistivity. 12% MC approximates air-dry conditions commonly encountered in service.
Reference:
- Wood Handbook - Wood as an Engineering Material (2010) - Forest Products Laboratory, United States Forest Service.