Heat Transfer Coefficient Converter
The heat transfer coefficient (U-value) characterizes how well a material or assembly conducts heat. Higher = more heat flow. Used in building insulation, heat exchangers.
Common Heat Transfer Coefficient Conversions
| From | To |
|---|---|
| 1 W/(m²·K) | 0.1761 BTU/(h·ft²·°F) |
| 1 BTU/(h·ft²·°F) | 5.678 W/(m²·K) |
| Typical window (double) | ~1.4 W/(m²·K) |
| R-13 wall | ~0.072 W/(m²·K) |
Heat Transfer Coefficient Unit Definitions
- W/(m²·K)
- SI unit: watts per square meter per kelvin.
- BTU/(h·ft²·°F)
- Imperial unit: British thermal units per hour per square foot per degree Fahrenheit.
Frequently Asked Questions
What is a good U-value for walls?
Modern insulated walls achieve U ~ 0.15–0.20 W/(m²·K). Passive houses target <0.15.
How does R-value relate to U-value?
U = 1/R (when using matching units). R-13 ≈ U = 0.077 in imperial, or RSI 2.3 ≈ U = 0.43 W/(m²·K).
What is the U-value of a single vs double-pane window?
Single-pane glass: U ≈ 5.8 W/(m²·K). Double-pane with air gap: U ≈ 2.7. Triple-pane with gas fill: U ≈ 0.8. Lower is better for energy efficiency.