U-value

[ yoo-val-yoo ]
/ ˈyuˌvæl yu /

noun

a measure of the flow of heat through an insulating or building material: the lower the U-value, the better the insulating ability.
Compare R-value.

Origin of U-value

1945–50; U, symbol for internal energy
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019