399 W/m²·K to BTU/hr·ft²·°F

399 W/m²·K = 70.268 BTU/hr·ft²·°F

W/m²·KBTU/hr·ft²·°F
384 W/m²·K67.6264
389 W/m²·K68.5069
394 W/m²·K69.3875
39970.268
404 W/m²·K71.1486
409 W/m²·K72.0291
414 W/m²·K72.9097

399 W/m²·K = 70.268 BTU/hr·ft²·°F

Formula

1 W/(m²·K) = 0.176110 BTU/(hr·ft²·°F) · 1 BTU/(hr·ft²·°F) = 5.67826 W/(m²·K)