Convert Degree Fahrenheit per watt to Hour-degree Fahrenheit per BTU
Convert Degree Fahrenheit per watt (°F/W) to Hour-degree Fahrenheit per BTU (h·°F/BTU) instantly and accurately.
Conversion Formula
h·°F/BTU = °F/W × 0.2930710702
About Degree Fahrenheit per watt
The degree Fahrenheit per watt (°F/W) equals exactly 5/9 K/W ≈ 0.5556 K/W. It appears in US power electronics datasheets and legacy JEDEC thermal specifications where junction-to-case resistance is reported in °F/W rather than °C/W or K/W. A device rated 5 °F/W has R = 5 × 5/9 ≈ 2.78 K/W. 1 °F/W = 5/9 K/W.
About Hour-degree Fahrenheit per BTU
The h·°F/BTU equals (5/9 × 3600)/1055.05585262 K/W ≈ 1.8956 K/W. It is the traditional US unit for thermal resistance in HVAC, building science, and insulation engineering. A pipe fitting with R = 1 h·°F/BTU passes 1 BTU/h per °F driving difference. Appears in ASHRAE handbooks, ASTM C177, and older US plumbing codes. 1 h·°F/BTU ≈ 1.8956 K/W.
Quick Reference Table
| Degree Fahrenheit per watt (°F/W) | Hour-degree Fahrenheit per BTU (h·°F/BTU) |
|---|---|
| 1 °F/W | 0.293071 h·°F/BTU |
| 2 °F/W | 0.586142 h·°F/BTU |
| 5 °F/W | 1.46536 h·°F/BTU |
| 10 °F/W | 2.93071 h·°F/BTU |
| 25 °F/W | 7.32678 h·°F/BTU |
| 50 °F/W | 14.6536 h·°F/BTU |
| 100 °F/W | 29.3071 h·°F/BTU |