What Is Low-E Windows?

There are three main applications of Low-E coatings for residential windows:

LoE 180 – With a glass U-Factor of just 0.26 and an SHGC of 0.69, Low-E 180 Glass is an excellent basic product for passive solar applications. By blocking heat loss to the outside of the glass, the high solar gain glass keeps homes warm in winter and cool in summer.

LoE 272 – Low-E 272 Glass delivers year-round comfort, reflecting an intermediate level of heat back into the room in winter and rejecting the sun’s heat and uv rays in summer. This product’s patented coating provides clarity and high-performance low-solar control, reducing window heat gain by 50% compared to ordinary glass.

LoE 366 – The ultimate performance glass, Low-E 366 provides the highest levels of year-round comfort and greatest energy savings. Its patented coating offers an ideal balance of solar control and high visibility. Blocking up to 95% of the sun’s damaging rays, Low-E 366 glass sets a new standard in energy performance.

Although historically Low-E coating was applied in a “soft-coat”(low heat loss, low solar gain) and “hard-coat” (moderate heat loss, high solar gain), recent developments in technology are erasing the differences between the different low-E applications.

While it is good to choose an energy-efficient product from the start, it is easy to optimize your window replacement by selecting low-E properties for your exact needs. Windows that face south or east can maximize the passive solar energy intake with high solar gain low-E. Conversely, you may want to have a low solar gain glazing on west-facing windows as it often helps keep the room cooler in the summertime. Low solar gain coating is also good for north facing windows as it allows for the least amount of heat loss in windows that get minimal sunlight.