Doors, Window, Glass and Curtain Wall Terminology...
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

U value
a measurement of heat transmission. The U value of a window is measured by the number of BTU's that will pass through each square foot of area per degree of temperature difference from one side of the window to the other (the lower, the better). U value = the number 1 divided by the R value.
back to top

united inches (UI)
the sum total of one window width and one window height expressed in inches.
back to top