U and R Values Explained

Customers at The Window Man's three Northern Virginia locations are often confused about (U) and (R) values and how they rate a window's insulation capabilities.

One way that insulation is created is with dead-air space between panes of glass. Therefore a double-paned window gives more insulation than a single-paned one. Other factors contribute to the insulation qualities of a window, such as the gasket, the material type, and the gas used in a gas-filled window. The U/R value tells how the product insulates. It is a formula derived from the efficiency of the product, and that formula takes into account many of the factors just mentioned. A good R measurement is a high one, while a good U measurement is low since U is the reciprocal of the R. Homeowners are more interested in the R value, while builders are interested in the U value.