What is the “R-Value” of CertainTeed windows?
You’ve probably heard of the “R-Value” rating used in relation to insulation products. But “U-Value” is the tool the window industry uses in the objective ratings comparisons established by the National Fenestration Ratings Council. U-Value measures the rate of heat flow through a glazing system — the lower the U-Value, the better the insulating quality of the window. Center of the glass U-Values measure the performance of the glass system. Total unit U-Values measure the performance of the entire window, taking into account frame, sash, airspace, the spacer between the panes, as well as the glass. U-Value can be compared to R-Value – which is the resistance of a material to heat flow — by dividing 1 by the U-Value. (Thus, a U-Value of 0.5 equals an R-Value of 2.) CertainTeed has developed Thermaflect®, a proprietary glazing system with a unique, two-layer, low emissive (Low “E”) coating on the glass. It selects the most beneficial wavelengths of light and heat to let through, and re
