What is being measured?
Thermal resistance is a temperature-difference to heat-flow relationship for a specified object or model. It is distinct from area-normalized thermal insulance.
Temperature difference per power. This is total thermal resistance; building R-value is area-normalized thermal insulance.
Meaning of °F/W
Fahrenheit degrees per watt uses the symbol °F/W in this library and measures thermal resistance. Under the stated reference convention, 1 °F/W = approximately 0.555555555556 K/W. This equivalence changes how a known value is written. It does not increase measurement accuracy or establish whether a measurement is appropriate to a real application.
Conversion method
Multiply the value by the source factor (0.55555555555555555555555555555555555555555555555556), then divide by the target factor (1). The factor ratio expresses the same thermal resistance measurement in the other unit.
Worked example
For a known value of 10 °F/W, the reference conversion gives 5.55555555556 K/W. Converting that result back gives approximately 10 °F/W. This reverse check helps catch a reversed factor, but matching round-trip arithmetic alone does not independently verify a source definition.
Common reference values
| Input (°F/W) | Reference equivalent (K/W) |
|---|---|
| 1 | 0.555555555556 |
| 5 | 2.77777777778 |
| 10 | 5.55555555556 |
| 25 | 13.8888888889 |
| 50 | 27.7777777778 |
| 100 | 55.5555555556 |
Compare one °F/W with other units
| Target unit | Equivalent of 1 °F/W | Definition guide |
|---|---|---|
| Kelvins per watt (K/W) | 0.555555555556 | Read definition |
| Kelvins per kilowatt (K/kW) | 555.555555556 | Read definition |
Precision and common mistakes
- Keep the source and target quantity consistent. A matching symbol is not enough to establish a compatible definition.
- Record the original measurement precision. Showing twelve significant digits in a table does not make a rounded input more precise.
- Check symbol capitalization, prefixes and any regional convention in the source. Use the displayed unit definition rather than a similarly named unit.
- Factors involving repeating fractions or π use finite numerical precision. Round the final answer to the precision justified by your input.
Use a working converter
- Thermal resistance converter
- Fahrenheit degrees per watt to Kelvins per watt converter
- Fahrenheit degrees per watt to Kelvins per kilowatt converter
Source and verification scope
Examples and tables are computed from the versioned unit definitions used by the linked converters. The source access dates appear below. Computandum is independent of the cited organizations; a citation does not mean that a publisher endorses this page or an actual project.