Thermal Resistance Converter
Convert thermal resistance between K/W (°C/W), R-value, and °F·h/BTU. Used in semiconductor datasheets (junction-to-case) and building insulation ratings.
Common Thermal Resistance Conversions
| From | To |
|---|---|
| 1 K/W | 0.52750 °F·h/BTU |
| 1 °F·h/BTU | 1.8956 K/W |
| R-1 insulation | 0.176 m²·K/W |
| R-13 insulation (US) | 2.29 m²·K/W |
Thermal Resistance Unit Definitions
- K/W (or °C/W)
- SI unit. Used in electronics for junction temperature calculations.
- R-value (ft²·°F·h/BTU)
- US unit for insulation. Higher = better insulation.
- RSI (m²·K/W)
- Metric R-value.
Frequently Asked Questions
What does thermal resistance mean for a CPU heatsink?
A heatsink with 0.5 °C/W means for every watt dissipated, the temperature rises 0.5 °C above ambient. A 65 W CPU with 0.5 °C/W heatsink runs ~32.5 °C above room temperature.
What is R-value in building insulation?
R-value (ft²·°F·h/BTU) rates insulation. Higher = better. R-13 is standard wall insulation; R-38 is recommended for attics in cold climates.
How do you calculate junction temperature of a transistor?
Tj = Ta + (Pd × Rθja), where Ta is ambient, Pd is power dissipated, and Rθja is junction-to-ambient thermal resistance from the datasheet.