|
|
Material |
kt (in Watts per meter per Kelvin) |
|
|
|
|
|
Conductors |
Aluminum |
237 |
|
|
Copper |
401 |
|
|
Gold |
318 |
|
|
Iron |
80.4 |
|
|
Lead |
353 |
|
|
Silver |
429 |
|
|
Steel |
46 |
|
|
Diamond |
2300 |
|
|
|
|
|
|
|
|
|
Insulators |
Nitrogen |
0.0234 |
|
|
Air (27oC) |
0.026 |
|
|
Asbestos |
0.08 |
|
|
Pine |
0.11 |
|
|
Helium |
0.138 |
|
|
Oak |
0.15 |
|
|
Hydrogen |
0.172 |
|
|
Concrete |
0.19 – 1.3 |
|
|
Rubber |
0.2 |
|
|
Ice |
0.592 |
|
|
Water |
0.609 |
|
|
Glass |
0.7 – 0.9 |
|
|
|
|
|
Material |
R-value |
|
|
|
|
Air film |
0.17 |
|
½ in. thick drywall |
0.45 |
|
Flat glass (0.125 in. thick) |
0.89 |
|
1 in. thick hardwood siding |
0.91 |
|
3.5 in. dead air space |
1.01 |
|
Insulating glass (0.25 air gap) |
1.54 |
|
1 in. thick carpet |
2.08 |
|
1 in. thick cellulose fiber |
3.70 |
|
4 in. thick brick |
4.00 |
|
1 in. expanded polystyrene |
4.00 |
|
1 in. thick fiberglass batting |
4.35 |
|
1 in. extruded polystyrene |
5.00 |
|
1 in. urethane foam |
5.75 |