Low E value

niceneasy · **Joined:** Wed Sep 30, 2009 6:14 pm **Posts:** 5

On the nfrc site under Low-E, what does a .207 vs an .024 signify and is either number indicative of a better window?

Skydawggy · **Posted:** Wed Oct 07, 2009 7:28 pm

It's either a .27 or a .24. That number indicates either the U-factor or the Solar Heat Gain Coefficient. Whether higher or lower is better depends on where you live. There would not be much of a difference in heating and cooling costs between the 2.

niceneasy · **Joined:** Wed Sep 30, 2009 6:14 pm **Posts:** 5

I am not referring to the U factor. This number is located under the column label of Low-E and states .027(2) with an OKNA window and .204(2), .204(5) for a BF Rich window.

shamu · **Joined:** Tue Nov 06, 2007 7:20 pm **Posts:** 186

That number is the Emissivity Value of the glass. How much heat it absorbs and emits. The number in () is the surface or surfaces the coating is located. A lower number indicates the glass will have more reflective properties. I would still put more weight on the overall U-vale of the entire window when making a buying decision.

Low E value

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