Cardinal glass, a major supplier for both Andersen and Jeld-Wen windows, recently released a revolutionary coating that gives a fantastic drop in u-rating compared to previous generations of windows. In the past, the only way to get a better insulated window was to add additional panes to the units. This can be a great option for energy efficiency, the drawback is triple pane windows are expensive. The new coating, called “Smartsun” in Andersen windows and “i89” in Jeld-Wen windows, reduces the u-rating and SHGC. What this means for you is windows that were previously an R-3 rating now can jump to an R-4 at a fraction of the cost of tripe-pane windows.

Definitions:

U-rating – the thermal resistivity of a window, the lower the number, the slower heat transfers through the window. U-rating is the inverse rating of R-value.

SHGC – Solar Heat Gain Coefficient. A rating that shows the percentage of solar radiation that makes it through your window transferring to heat on the inside of your home.

For more info: http://www.cardinalcorp.com/products/coated-glass/loe-i89/