Convert BTU/(h·ft²·°F) to Watts per Square Metre Kelvin
1 BTU per hour square foot degree Fahrenheit (BTU/(h·ft²·°F)) = 5.678263341 watts per square metre kelvin (W/(m²·K)). 1 W/(m²·K) = 0.1761101837 BTU/(h·ft²·°F). Example: 0.3 BTU/(h·ft²·°F) = 0.3 × 5.678263341 = 1.703479002 W/(m²·K).
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1 BTU/(h·ft²·°F) = 5.678263341 W/(m²·K)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk BTU per hour square foot degree Fahrenheit to watt per square metre kelvin converter to paste a column from Excel.
How to Convert BTU/(h·ft²·°F) to Watt per Square Metre Kelvin
- 1 BTU/(h·ft²·°F) = 5.678263341 W/(m²·K)
- 1 W/(m²·K) = 0.1761101837 BTU/(h·ft²·°F)
- Example: convert 0.3 BTU/(h·ft²·°F) to W/(m²·K): 0.3 BTU/(h·ft²·°F) = 0.3 × 5.678263341 W/(m²·K) = 1.703479002 W/(m²·K)
Formula
W/(m²·K) = BTU/(h·ft²·°F) × 5.678263341113
Derivation from SI units:
- 1 BTU_IT/(h·ft²·°F) = 1055.05585262 J ÷ (3600 s × 0.09290304 m² × 5/9 K) = 5.678263341 W/(m²·K) (exact)
- The SI unit of heat transfer coefficient and thermal transmittance (U-value): heat flow (W) per square metre per kelvin
Both units are defined exactly, so the factor is exact. BTU/(h·ft²·°F) definition: BTU per hour square foot degree Fahrenheit; Watt per Square Metre Kelvin definition: watt per square metre kelvin.
Worked examples
- A window with a U-factor of 0.3 BTU/(h·ft²·°F) is 1.703479002 W/(m²·K).
0.3 BTU/(h·ft²·°F) × 5.678263341 = 1.703479002 W/(m²·K) - A heat exchanger with U = 100 BTU/(h·ft²·°F) is 567.8263341 W/(m²·K).
100 BTU/(h·ft²·°F) × 5.678263341 = 567.8263341 W/(m²·K)
BTU/(h·ft²·°F) to Watt per Square Metre Kelvin conversion table
| BTU/(h·ft²·°F) | Watts per Square Metre Kelvin (W/(m²·K)) |
|---|---|
| 0.03 BTU/(h·ft²·°F) | 0.1703479002 W/(m²·K) |
| 0.05 BTU/(h·ft²·°F) | 0.2839131671 W/(m²·K) |
| 0.25 BTU/(h·ft²·°F) | 1.419565835 W/(m²·K) |
| 0.5 BTU/(h·ft²·°F) | 2.839131671 W/(m²·K) |
| 1 BTU/(h·ft²·°F) | 5.678263341 W/(m²·K) |
| 2 BTU/(h·ft²·°F) | 11.35652668 W/(m²·K) |
| 5 BTU/(h·ft²·°F) | 28.39131671 W/(m²·K) |
| 50 BTU/(h·ft²·°F) | 283.9131671 W/(m²·K) |
| 100 BTU/(h·ft²·°F) | 567.8263341 W/(m²·K) |
| 250 BTU/(h·ft²·°F) | 1419.565835 W/(m²·K) |
| 500 BTU/(h·ft²·°F) | 2839.131671 W/(m²·K) |
Where it's used
US U-factors and heat transfer coefficients in BTU/(h·ft²·°F) are converted to W/(m²·K) for SI design, EN standards and international datasheets. Multiply by about 5.678.
BTU/(h·ft²·°F) to other heat transfer coefficient units
| Conversion | 1 BTU/(h·ft²·°F) equals |
|---|---|
| BTU per hour square foot degree Fahrenheit to watt per square metre kelvin | 5.678263341 W/(m²·K) |
| BTU per hour square foot degree Fahrenheit to kilowatt per square metre kelvin | 0.005678263341 kW/(m²·K) |
| BTU per hour square foot degree Fahrenheit to kilocalorie per hour square metre degree Celsius | 4.882427636 kcal/(h·m²·°C) |
| BTU per hour square foot degree Fahrenheit to watt per square centimetre kelvin | 0.0005678263341 W/(cm²·K) |
| BTU per hour square foot degree Fahrenheit to calorie per second square centimetre degree Celsius | 0.000135713751 cal/(s·cm²·°C) |
Frequently asked questions
How do I convert a US U-factor to a metric U-value?
Multiply by 5.678263: a U-0.30 window is 1.703 W/(m²·K).
How do I convert a US R-value to RSI?
Multiply by 0.1761 (the reciprocal of 5.678): R-19 is about RSI 3.35 m²·K/W.
How many watts per square metre kelvin are in 1 BTU per hour square foot degree Fahrenheit?
1 BTU/(h·ft²·°F) = 5.678263341 W/(m²·K).
How do I convert BTU per hour square foot degree Fahrenheit to watts per square metre kelvin?
Multiply the value in BTU/(h·ft²·°F) by 5.678263341. For example, 0.3 BTU/(h·ft²·°F) × 5.678263341 = 1.703479002 W/(m²·K).
Is the BTU/(h·ft²·°F) to W/(m²·K) conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "British thermal unit_IT per hour square foot degree Fahrenheit [Btu_IT/(h · ft² · °F)]".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert BTU/(h·ft²·°F) to Watts per Square Metre Kelvin. Retrieved October 25, 2026, from https://scientificconverters.com/heat-transfer-coefficient/btu-per-hour-square-foot-fahrenheit-to-watts-per-square-meter-kelvin/
IEEE
Scientific Converters, "Convert BTU/(h·ft²·°F) to Watts per Square Metre Kelvin," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/heat-transfer-coefficient/btu-per-hour-square-foot-fahrenheit-to-watts-per-square-meter-kelvin/