Though low-emissivity, or low-e, coatings are now standard fare on many windows, all low-e coatings aren't alike. Different types of coatings transmit varying amounts of visible, infrared (IR), and ultraviolet (UV) radiation. But do these differences really matter? I believe they do. As a designer, I've learned to fine-tune the comfort and energy performance of my buildings by using different windows on different facades. While the effect may be subtle on a small ranch house, the results in a large custom home can be dramatic. Low-E and R-Value A low-e coating is like a specialized mirror in that it reflects radiant heat back to where it came from (see illustration below). It can increase the center- of-glass insulating value
