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The Benefits of Low-E Window Coatings

If you’ve been contemplating getting window replacements recently, you’ve probably come across the term Low-E in your search for the most energy efficient windows. You may have thought to yourself, “why should I get a stupid window coating that costs more when I’m already spending too much as it is on these window replacements?” And you’re not to be blamed either, because windows can be a rather expensive investment, but here’s the catch: if you choose the proper installments you could be saving huge due to lower overall energy use and as a result – lower energy costs.

A strong point indeed, but what exactly does low emittance glass DO?

For the purposes of this blog we’ll be discussing just one type of low-e glass windows, and that’s the kind that mostly benefits those living in extreme heat climates. This specific type of low thermal emittance glass is created by adding a “double-glaze” of low emissivity material to the inner panes of the window. The difference between the types of low-e windows is actually in the low-e coatings themselves. For cooling-dominated environments, where temperatures are frequently hotter, it’s essential that your low-e coatings provide the lowest possible solar gains. Basically, you want your windows to reflect as much heat as possible in the summer, and retain as much indoor heat as they can in the winter.

If you live in the Tucson area, your best bet will be whichever windows offer the lowest solar heat gain coefficient (SHGC) along with a suitable U-Factor (< .60). The less solar heat you allow to be transmitted through your windows, the less energy you will be using in order to cool your home. The amount of solar heat reduction is estimated in percentages, so this means the hotter it gets the more overall heat your low-e windows will be keeping out. Don’t worry about turning your house into a dungeon either. Low-E coatings applied for environments like those in Tucson are specifically formulated to allow high visible light transmittance along with the lowest possible solar gains. In other words, low-e coatings are much more advanced than window tints designed to lower solar heat gains by reducing the amount of visible light that gets transmitted.

At this point you may be thinking, “seriously, that’s all it is, is just some ‘special’ coating they apply?”

True, sort of, but the coatings aren’t necessarily inexpensive, and don’t forget the argon gas filling between those glazed double panes. Window manufacturers have learned that in combination with low-e coatings, adding a fill of argon (or in certain cases, krypton) gas helps to reduce the conductance of the air in the space between the window panes. Argon gas moves slower on a molecular level than you’re typical mixture of oxygen and carbon compounds found in the air. This makes the air space between your windows less conductive, thus minimizing the convection currents within that space. As a result your windows experience even less overall heat transfer from outside and inside.

Now you know what you’re getting when you buy Low-E windows, so all you need to do is pick a store!

Well, if you’re in the Tucson or areas, let’s just say American Openings Windows is your best bet. Why? Because, American Openings Windows custom manufactures their windows specifically to fit your home, which in turn saves you up to 50% on the cost of window installation. They also carry Energy Star certified windows too if you’re interested in the highest quality energy efficient windows. Oh, and did I forget to mention the great service you’ll receive, and that’s on top of all the money you’ll be saving every day from then onward! Whew, what a deal!

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Contact American Openings during normal business hours at (520) 664-1202.


6885 E. Southpoint Road
Tucson, Arizona 85756
Phone: (520) 664-1202
Toll-Free: (800) 430-3385