What is U-value and how does it relate to R-value rating?
R-value and U-value are reciprocal to one another. The term U-value is measured by the amount of heat that escapes a surface-a wall, ceiling, or window. R-Value is measured by insulation value. How many glass layers there are in a window to the type of gas that is between the panes of glass, are some of the basis of this measurement. The higher the R-value, the better insulated are walls and ceilings. The lower the U-value, the better job a window does in keeping out heat and cold.