Low Emissivity Coatings


Low E, Low E2, or Low E3?

In this article I have decided to write about a question that causes confusion for
many customers in today’s window market.


What Low-E coating should I buy for my replacement windows?


The answer is all of them. As cryptic as this answer might seem all three of the major glass coatings available are in my opinion good for your window, albeit each coating has its pros and cons, along with regional necessities.  Mainly I will focus on products available from Pilkington and Cardinal as they generally are the most common coatings available in the North American market. 
The “E” in Low-E coatings stands for emissivity.  These are specially designed coatings, often based on metallic oxides e.g. silver, and are applied to one or more surfaces of insulated glass. These coatings reflect radiant infrared energy, thus tending to keep radiant heat on the same side of the glass from which it originated, while letting visible light pass. This often results in more efficient windows because radiant heat originating from indoors in winter is reflected back inside, while infrared heat radiation from the sun during summer is reflected away, keeping it cooler inside.  LoĒ²-272 from Cardinal, and Solar-E from Pilkington are very good at reflecting heat back outdoors, while Low-E Energy Advantage from Pilkington and LoĒ-179 High Solar Gain Glass from Cardinal are very good at reflecting heat back indoors with maximum heat gain in general from the sun.  I personally prefer the LoĒ³-366 coating from Cardinal.  Although it has a slightly higher cost than other coatings, I believe it best combines the elements of solar heat gain with solar reflection.  Also the tint is the most attractive.  LoĒ³-366 is very new and was just introduced at the end of 2010.

Manufactured by:



Low-E (Energy Advantage)

Manufactured by:



LoĒ³-366 Ultimate Performance Glass
LoĒ²-272 All Climate Glass
LoĒ²-270 All Climate Solar Control Glass
LoĒ²-240 Glare Control Glass
LoĒ-179 High Solar Gain Glass
LoĒ-i81 Enhanced Performance Glass