BTU·in/(h·ft²·°F)

The BTU inch per hour square foot degree Fahrenheit is the US "k-value" unit for insulation: the heat flow through one inch of material. 1 BTU·in/(h·ft²·°F) = 0.1442 W/(m·K); fibreglass is about 0.25–0.27.

Symbol: BTU·in/(h·ft²·°F) (ASCII: BTU*in/(h*ft2*F))

Quantity: thermal conductivity (k, λ)

SI relation: 1 BTU·in/(h·ft²·°F) = 0.1442278888643 W/(m·K) (exact)

Derivation: 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)

Exact: yes, by definition

Typical uses

US insulation k-values (ASTM C177, C518)
R-value per inch (R = 1/k)
Building and pipe insulation

Convert BTU inch per hour square foot degree Fahrenheit to other units

1 BTU·in/(h·ft²·°F) in other thermal conductivity units
Conversion	1 BTU·in/(h·ft²·°F) equals	Reverse
BTU inch per hour square foot degree Fahrenheit to watt per metre kelvin	0.1442278889 W/(m·K)	watt per metre kelvin to BTU inch per hour square foot degree Fahrenheit
BTU inch per hour square foot degree Fahrenheit to BTU per hour foot degree Fahrenheit	0.08333333333 BTU/(h·ft·°F)	BTU per hour foot degree Fahrenheit to BTU inch per hour square foot degree Fahrenheit
BTU inch per hour square foot degree Fahrenheit to milliwatt per metre kelvin	144.2278889 mW/(m·K)	milliwatt per metre kelvin to BTU inch per hour square foot degree Fahrenheit
BTU inch per hour square foot degree Fahrenheit to kilocalorie per hour metre degree Celsius	0.124013662 kcal/(h·m·°C)	kilocalorie per hour metre degree Celsius to BTU inch per hour square foot degree Fahrenheit
BTU inch per hour square foot degree Fahrenheit to watt per centimetre kelvin	0.001442278889 W/(cm·K)	watt per centimetre kelvin to BTU inch per hour square foot degree Fahrenheit
BTU inch per hour square foot degree Fahrenheit to calorie per second centimetre degree Celsius	0.0003447129275 cal/(s·cm·°C)	calorie per second centimetre degree Celsius to BTU inch per hour square foot degree Fahrenheit

Open the Thermal Conductivity Converter to convert any value between all units.

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)]".

Last reviewed: 2026-10-15. 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). BTU·in/(h·ft²·°F). Retrieved October 25, 2026, from https://scientificconverters.com/units/btu-inch-per-hour-square-foot-fahrenheit/

IEEE

Scientific Converters, "BTU·in/(h·ft²·°F)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/units/btu-inch-per-hour-square-foot-fahrenheit/