Convert Hour-degree Fahrenheit per BTU to Degree Fahrenheit per watt
Convert Hour-degree Fahrenheit per BTU (h·°F/BTU) to Degree Fahrenheit per watt (°F/W) instantly and accurately.
Conversion Formula
°F/W = h·°F/BTU × 3.412141633
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.
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.
Quick Reference Table
| Hour-degree Fahrenheit per BTU (h·°F/BTU) | Degree Fahrenheit per watt (°F/W) |
|---|---|
| 1 h·°F/BTU | 3.41214 °F/W |
| 2 h·°F/BTU | 6.82428 °F/W |
| 5 h·°F/BTU | 17.0607 °F/W |
| 10 h·°F/BTU | 34.1214 °F/W |
| 25 h·°F/BTU | 85.3035 °F/W |
| 50 h·°F/BTU | 170.607 °F/W |
| 100 h·°F/BTU | 341.214 °F/W |