High-quality windows are critical and there are two metrics you can use to compare windows, no matter the brand. In this video, Matt Risinger, master builder, explains what is on window labels, and what it all means. An energy level sticker is the same across all manufacturers. The two metrics are the U-Factor and for the windows, Risinger is showing us, the U-Factor comes in at 0.28. The U-Factor represents the insulation performance of the window. Risinger explains how this number relates to one we're more used to in building, the R-Factor. We should be looking for a lower number in U-Factors. The newest energy code (2012) requires .4 or less for Climate Zone 2 in the southern U.S. where it is hot and humid. The second number that is important is the Solar Heat Gain Coefficient (SHGC). When the sun's rays hit the window, how much of the sun's energy will reflected to the outside, and how much will heat up your house? In the demonstration, 0.18 means that approximately 20% is making it into the inside of the home. Code for the region is .25 or less, and the lower the number, the better. Risinger also indicates that it makes sense to use Cardinal low-E 366 glass in this environment, which is a double-pane argon filled low-E 366 glass. Cardinal is offered by all popular window manufacturers.