Convert BTU·in/(h·ft²·°F) to Watts per Metre Kelvin
1 BTU inch per hour square foot degree Fahrenheit (BTU·in/(h·ft²·°F)) = 0.1442278889 watts per metre kelvin (W/(m·K)). 1 W/(m·K) = 6.933471799 BTU·in/(h·ft²·°F). Example: 0.25 BTU·in/(h·ft²·°F) = 0.25 × 0.1442278889 = 0.03605697222 W/(m·K).
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1 BTU·in/(h·ft²·°F) = 0.1442278889 W/(m·K)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk BTU inch per hour square foot degree Fahrenheit to watt per metre kelvin converter to paste a column from Excel.
How to Convert BTU·in/(h·ft²·°F) to Watt per Metre Kelvin
- 1 BTU·in/(h·ft²·°F) = 0.1442278889 W/(m·K)
- 1 W/(m·K) = 6.933471799 BTU·in/(h·ft²·°F)
- Example: convert 0.25 BTU·in/(h·ft²·°F) to W/(m·K): 0.25 BTU·in/(h·ft²·°F) = 0.25 × 0.1442278889 W/(m·K) = 0.03605697222 W/(m·K)
Formula
W/(m·K) = BTU·in/(h·ft²·°F) × 0.1442278888643
or W/(m·K) = BTU·in/(h·ft²·°F) ÷ 6.933471798516
Derivation from SI units:
- 1 BTU_IT·in/(h·ft²·°F) = 1055.05585262 J × 0.0254 m ÷ (3600 s × 0.09290304 m² × 5/9 K) = 0.1442278889 W/(m·K) (exact)
- The SI unit of thermal conductivity: heat flow (W) per metre of thickness per kelvin of temperature difference
Both units are defined exactly, so the factor is exact. BTU·in/(h·ft²·°F) definition: BTU inch per hour square foot degree Fahrenheit; Watt per Metre Kelvin definition: watt per metre kelvin.
Worked examples
- Fibreglass batt with a k-value of 0.25 BTU·in/(h·ft²·°F) is 0.03605697222 W/(m·K).
0.25 BTU·in/(h·ft²·°F) × 0.1442278889 = 0.03605697222 W/(m·K) - Polyiso foam at 0.16 BTU·in/(h·ft²·°F) is 0.02307646222 W/(m·K).
0.16 BTU·in/(h·ft²·°F) × 0.1442278889 = 0.02307646222 W/(m·K)
BTU·in/(h·ft²·°F) to Watt per Metre Kelvin conversion table
| BTU·in/(h·ft²·°F) | Watts per Metre Kelvin (W/(m·K)) |
|---|---|
| 0.15 BTU·in/(h·ft²·°F) | 0.02163418333 W/(m·K) |
| 0.16 BTU·in/(h·ft²·°F) | 0.02307646222 W/(m·K) |
| 0.2 BTU·in/(h·ft²·°F) | 0.02884557777 W/(m·K) |
| 0.22 BTU·in/(h·ft²·°F) | 0.03173013555 W/(m·K) |
| 0.25 BTU·in/(h·ft²·°F) | 0.03605697222 W/(m·K) |
| 0.27 BTU·in/(h·ft²·°F) | 0.03894152999 W/(m·K) |
| 0.3 BTU·in/(h·ft²·°F) | 0.04326836666 W/(m·K) |
| 0.5 BTU·in/(h·ft²·°F) | 0.07211394443 W/(m·K) |
| 1 BTU·in/(h·ft²·°F) | 0.1442278889 W/(m·K) |
| 5 BTU·in/(h·ft²·°F) | 0.7211394443 W/(m·K) |
Where it's used
US insulation k-values in BTU·in/(h·ft²·°F) from ASTM C518 reports are converted to W/(m·K) λ-values for European and ISO comparisons. Multiply by about 0.1442.
BTU·in/(h·ft²·°F) to other thermal conductivity units
| Conversion | 1 BTU·in/(h·ft²·°F) equals |
|---|---|
| BTU inch per hour square foot degree Fahrenheit to watt per metre kelvin | 0.1442278889 W/(m·K) |
| BTU inch per hour square foot degree Fahrenheit to BTU per hour foot degree Fahrenheit | 0.08333333333 BTU/(h·ft·°F) |
| BTU inch per hour square foot degree Fahrenheit to milliwatt per metre kelvin | 144.2278889 mW/(m·K) |
| BTU inch per hour square foot degree Fahrenheit to kilocalorie per hour metre degree Celsius | 0.124013662 kcal/(h·m·°C) |
| BTU inch per hour square foot degree Fahrenheit to watt per centimetre kelvin | 0.001442278889 W/(cm·K) |
| BTU inch per hour square foot degree Fahrenheit to calorie per second centimetre degree Celsius | 0.0003447129275 cal/(s·cm·°C) |
Frequently asked questions
How do I convert a k-value to a λ-value?
Multiply the k-value in BTU·in/(h·ft²·°F) by 0.1442279: k = 0.25 gives 0.03606 W/(m·K).
How many watts per metre kelvin are in 1 BTU inch per hour square foot degree Fahrenheit?
1 BTU·in/(h·ft²·°F) = 0.1442278889 W/(m·K).
How do I convert BTU inch per hour square foot degree Fahrenheit to watts per metre kelvin?
Multiply the value in BTU·in/(h·ft²·°F) by 0.1442278889, or divide it by 6.933471799. For example, 0.25 BTU·in/(h·ft²·°F) × 0.1442278889 = 0.03605697222 W/(m·K).
Is the BTU·in/(h·ft²·°F) to W/(m·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 inch per hour square foot degree Fahrenheit [Btu_IT · in/(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·in/(h·ft²·°F) to Watts per Metre Kelvin. Retrieved October 25, 2026, from https://scientificconverters.com/thermal-conductivity/btu-inch-per-hour-square-foot-fahrenheit-to-watts-per-meter-kelvin/
IEEE
Scientific Converters, "Convert BTU·in/(h·ft²·°F) to Watts per Metre Kelvin," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/thermal-conductivity/btu-inch-per-hour-square-foot-fahrenheit-to-watts-per-meter-kelvin/