What is Low-E glass and does it really work?

Low-E is an abbreviated term for Low-emissivity glass.  According to Wikipedia, Low-emissivity (Low-E) coatings are “microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radioactive heat flow.”  Gorell offers a an easy-to-understand explanation about how low-e works on its web site at http://www.gorell.com/pages/lower_energy_bills.cfm.

There are a couple of different types of Low-e coatings, hard coat and soft coat.  Hard-coat Low-E is an older technology that uses a layer of tin oxide.  The coating reflects the sun’s rays in summer and allows them in during the winter.  Soft-coat Low-e uses silver oxide in place of tin oxide for the coating.  In simple terms, the most reflective surface in your house is a mirror.  The back of a mirror is coated with silver oxide.  If a mirror does a perfect job of reflecting your image, imagine how well it reflects the sun’s rays in the winter.  Of course, in the winter, soft-coat Low-E allows passive heat to come into your house.

There is no question in the window industry about whether Low-E glass works.  It is extremely effective.  www.Gorell.com offers a high-performance glass chart so you can determine which type of Low-E glass is right for you.  The chart can be found at http://www.gorell.com/pages/glass_chart.htm.

Let me know how Low-E glass has worked for you.