in²·h·°F/BTU

square inch hour Fahrenheit per BTU

Areal thermal resistanceexact by definition

The square inch hour Fahrenheit per BTU is 1.222987382 × 10⁻³ m²·K/W, or exactly one 144th of a US R-value. It is the North American thermal interface unit, the imperial twin of °C·cm²/W: a grease at 0.1 °C·cm²/W is about 0.08 in²·h·°F/BTU.

1 in²·h·°F/BTU 0.0012229874 RSI (m²·K/W)