Thermal Conductivity

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.

Last updated: 17 July 2026Reviewed by: Vriksai editorial team — timber trade professionalsEditorial policy

Revision history

17 July 2026 — Site-wide audit — all tabulated values re-checked against listed sources

60Species computed

0.165Avg k (W/m·K)

0.087Best insulator (Paulownia)

0.274Highest (Lignum Vitae)

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.

60 species

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%
Thermally Modified Western Red CedarThuja plicata	0.102	9.80	0.38	6%
Sugi Japanese CedarCryptomeria japonica	0.111	9.01	0.38	12%
ThermoWood Spruce Thermo-DPicea 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 Thermo-DPinus sylvestris	0.124	8.06	0.48	6%
Kail Blue PinePinus wallichiana	0.128	7.81	0.45	12%
ThermoWood Radiata Pine Thermo-DPinus 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%
Thermally Modified LarchLarix 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%
Thermally Modified Siberian LarchLarix 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 Thermo-DBetula pubescens	0.154	6.49	0.62	6%
Sweet ChestnutCastanea sativa	0.155	6.45	0.56	12%
ThermoWood Ash Thermo-DFraxinus 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%
Thermally Modified OakQuercus 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%

How to read it: Lower k = better insulator. A timber-framed or solid-wood wall keeps heat in far better than masonry of the same thickness. Resistivity (the inverse) is shown for insulation context — higher means more resistance to heat flow. Values are computed from specific gravity at the moisture content listed (12% for solid wood, 6% for treated/ThermoWood at service); the USDA notes actual conductivity can vary up to 20%, and rises with moisture and temperature.

Sources

USDA FPL Wood Handbook GTR-190, Ch. 4 (thermal properties) — www.fpl.fs.usda.gov/documnts/fplgtr/fplgtr190

Common questions

Is wood a good insulator?

Yes. Wood holds far less heat flow than brick, concrete or steel. That is why wooden houses feel warmer and why saucepan handles are often wooden.

Does denser wood conduct more heat?

Yes. Heavier woods pass heat more easily, lighter woods insulate better. Moisture also matters — wet wood conducts more heat than dry wood.

Why does this matter for cladding and saunas?

For cladding, better insulation means lower heating bills. For saunas, you want wood that stays comfortable to touch even when the room is very hot — that is why aspen and thermally treated woods are popular there.

Thermal Conductivity

Related tools

Sources

Common questions