BTU/(h·°F)
BTU per hour Fahrenheit
Thermal conductanceexact by definition
The BTU per hour per Fahrenheit degree is the customary US unit of thermal conductance, equal to exactly 0.52752792631 W/K. The factor is exact by definition: the International Table BTU of 1055.05585262 J divided by 3600 seconds and by the 5/9 K Fahrenheit degree gives a terminating decimal. It is the product of a U-value in BTU/(h·ft²·°F) and an area in square feet, and it is what appears in a building's UA total.
Watch out: The Fahrenheit degree here is an interval, so no 32 enters the conversion. A wall with a UA of 100 BTU/(h·°F) loses 7000 BTU/h across a 70 F° difference, whatever the absolute temperatures happen to be.
| 1 BTU/(h·°F) | 0.52752793 W/K |