Thermal conductivity (k, in W/m·K) for 60 timber species, computed with the USDA Forest Products Laboratory formula. How fast each wood conducts heat — lower means a better natural insulator.
Wood is a natural insulator — far better than steel (~50 W/m·K) or concrete (~1.7). Its thermal conductivity depends almost entirely on density: light woods trap more air and insulate better. Values run from about 0.09 W/m·K for the lightest woods (paulownia, cedar) to 0.27 for the densest tropicals (lignum vitae, blackwood). These are computed at the service moisture content shown using the USDA Wood Handbook equation k = G(0.1941 + 0.004064×M) + 0.01864.
| Species ↕ | Conductivity k (W/m·K) ↕ | Resistivity (m·K/W) ↕ | Specific Gravity ↕ | at MC ↕ |
|---|---|---|---|---|
| PaulowniaPaulownia tomentosa | 0.087 | 11.49 | 0.28 | 12% |
| Western Red CedarThuja plicata | 0.096 | 10.42 | 0.32 | 12% |
| Thermowood Western Red Cedar ThermoDThuja plicata | 0.102 | 9.80 | 0.38 | 6% |
| Sugi Japanese CedarCryptomeria japonica | 0.111 | 9.01 | 0.38 | 12% |
| Thermowood Spruce ThermoDPicea abies | 0.117 | 8.55 | 0.45 | 6% |
| Spruce-Pine-Fir SPFPicea / Pinus / Abies spp. | 0.121 | 8.26 | 0.42 | 12% |
| Hinoki CypressChamaecyparis obtusa | 0.121 | 8.26 | 0.42 | 12% |
| Norway SprucePicea abies | 0.123 | 8.13 | 0.43 | 12% |
| Thermowood Pine ThermoDPinus sylvestris | 0.124 | 8.06 | 0.48 | 6% |
| Kail Blue PinePinus wallichiana | 0.128 | 7.81 | 0.45 | 12% |
| Thermowood Radiata Pine ThermoDPinus radiata | 0.128 | 7.81 | 0.50 | 6% |
| Hem-FirTsuga / Abies spp. | 0.128 | 7.81 | 0.45 | 12% |
| Western HemlockTsuga heterophylla | 0.128 | 7.81 | 0.45 | 12% |
| Accoya Acetylated Radiata PinePinus radiata | 0.130 | 7.69 | 0.51 | 6% |
| Deodar CedarCedrus deodara | 0.135 | 7.41 | 0.48 | 12% |
| Douglas FirPseudotsuga menziesii | 0.135 | 7.41 | 0.48 | 12% |
| Scots PinePinus sylvestris | 0.138 | 7.25 | 0.49 | 12% |
| Thermowood Larch ThermoDLarix decidua | 0.139 | 7.19 | 0.55 | 6% |
| American CherryPrunus serotina | 0.140 | 7.14 | 0.50 | 12% |
| Mango WoodMangifera indica | 0.143 | 6.99 | 0.51 | 12% |
| Southern Yellow PinePinus spp. (P. palustris, P. taeda) | 0.143 | 6.99 | 0.51 | 12% |
| Meranti Red LauanShorea spp. | 0.145 | 6.90 | 0.52 | 12% |
| African MahoganyKhaya ivorensis | 0.145 | 6.90 | 0.52 | 12% |
| Thermowood Siberian Larch ThermoDLarix sibirica | 0.148 | 6.76 | 0.59 | 6% |
| TeakTectona grandis | 0.152 | 6.58 | 0.55 | 12% |
| Rubber WoodHevea brasiliensis | 0.152 | 6.58 | 0.55 | 12% |
| Black WalnutJuglans nigra | 0.152 | 6.58 | 0.55 | 12% |
| European LarchLarix decidua | 0.152 | 6.58 | 0.55 | 12% |
| IrokoMilicia excelsa | 0.152 | 6.58 | 0.55 | 12% |
| Thermowood Birch ThermoDBetula pubescens | 0.154 | 6.49 | 0.62 | 6% |
| Sweet ChestnutCastanea sativa | 0.155 | 6.45 | 0.56 | 12% |
| Thermowood Ash ThermoDFraxinus excelsior | 0.163 | 6.13 | 0.66 | 6% |
| Bamboo Structural EngineeredBambusa / Dendrocalamus spp. | 0.164 | 6.10 | 0.60 | 12% |
| White AshFraxinus americana | 0.164 | 6.10 | 0.60 | 12% |
| Thermowood Oak ThermoDQuercus robur | 0.167 | 5.99 | 0.68 | 6% |
| Silver BirchBetula pendula | 0.167 | 5.99 | 0.61 | 12% |
| Yellow BirchBetula alleghaniensis | 0.169 | 5.92 | 0.62 | 12% |
| SapeleEntandrophragma cylindricum | 0.169 | 5.92 | 0.62 | 12% |
| Hard MapleAcer saccharum | 0.172 | 5.81 | 0.63 | 12% |
| Burma Teak Premium GradeTectona grandis | 0.179 | 5.59 | 0.66 | 12% |
| European OakQuercus robur | 0.181 | 5.52 | 0.67 | 12% |
| NeemAzadirachta indica | 0.184 | 5.43 | 0.68 | 12% |
| European BeechFagus sylvatica | 0.184 | 5.43 | 0.68 | 12% |
| KeruingDipterocarpus spp. | 0.186 | 5.38 | 0.69 | 12% |
| GarapaApuleia leiocarpa | 0.194 | 5.15 | 0.72 | 12% |
| SalShorea robusta | 0.198 | 5.05 | 0.74 | 12% |
| MerbauIntsia bijuga | 0.198 | 5.05 | 0.74 | 12% |
| Indian RosewoodDalbergia latifolia | 0.201 | 4.98 | 0.75 | 12% |
| Shisham SissooDalbergia sissoo | 0.201 | 4.98 | 0.75 | 12% |
| BalauShorea spp. | 0.208 | 4.81 | 0.78 | 12% |
| WengeMillettia laurentii | 0.213 | 4.69 | 0.80 | 12% |
| JarrahEucalyptus marginata | 0.218 | 4.59 | 0.82 | 12% |
| MassarandubaManilkara bidentata | 0.225 | 4.44 | 0.85 | 12% |
| BangkiraiShorea laevis | 0.225 | 4.44 | 0.85 | 12% |
| Spotted GumCorymbia citriodora | 0.225 | 4.44 | 0.85 | 12% |
| CumaruDipteryx odorata | 0.230 | 4.35 | 0.87 | 12% |
| EbonyDiospyros ebenum | 0.237 | 4.22 | 0.90 | 12% |
| Ipe LapachoHandroanthus serratifolius | 0.242 | 4.13 | 0.92 | 12% |
| African BlackwoodDalbergia melanoxylon | 0.257 | 3.89 | 0.98 | 12% |
| Lignum VitaeGuaiacum officinale | 0.274 | 3.65 | 1.05 | 12% |
