low e vs tempered windows

sruther2July 11, 2012

Hi, new to this forum. Have questions about getting a window installed in my home. I live in Co and I have a large south facing living room window that cracked because of heat stress. It had a tint film. Can any one give recommendations on a replacement glass? Low e solarban 60 or tempered. It's a window that gets lots of sun. Can you see a greenish tint looking out? Any advice welcomed. Thanks. Sr

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hi sruther2,

I am puzzled why you are dealing with the option of either tempered or LowE?

Tempering is for strengthening glass and LowE is for energy performance. There is absolutely no reason that I can think of that would require you to choose one or the other.

You will not see a color shift in the LowE under most normal viewing conditions. Very few people can tell if a window has a LowE coating when looking thru it which is why even professionls use LowE detectors.

However, if you are looking at the reflection of your interior lights at night then it is possible to detect a slight greenish tint in the reflected light from the coating - I can't imagine that being objectionable to anyone.

Do you have more details on the either/or of LowE versus tempered?


    Bookmark   July 11, 2012 at 2:30PM
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Unfortunately, windows with applied film are more prone to do this.

Who was the manufacturer of the film? 3M provides a supplemental warranty on glass where their film is installed if I am not mistaken.

    Bookmark   July 11, 2012 at 3:34PM
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Well, when I got estimates, one glass company suggested low e glass, and another suggested tempered. I'm not sure which to choose. Would the solarban 60 with a coating be a sufficient tint? With clear glass we will have to have it re tinted. But I was told by the glass co that once we re tint, they are no longer responsible for the glass. Does this sound right? I just do not know if we should get tempered glass with a film or low e glass. Will the coating be a sufficient tint? Thanks sr

    Bookmark   July 11, 2012 at 4:46PM
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The one company probably recommended tempered for a reason. It's probably very large. I take it you are not talking about a new window with frame, but just new glass from a glass company? And I take it you're not taking about double pane but single pane? That might be the confusion.

Go with a double pane unit, tempered on the inside only, with Low E2. Then you won't need tinting. Tinting FILM is not very reliable and seems to cause a LOT of problems in home units. Tinting is for cars.

However one more thing. If by tinting, you are talking about actual tinted glass, then that's different. That's where it's not a film, but an actual tint in the glass. I think that Low E2, at least, would eliminate the need for tinting for solar reasons.
There's my 2 cents.

    Bookmark   July 11, 2012 at 10:10PM
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Tempered glass is a strengthening and safety process. The glass inside shower doors is tempered (or laminated but most often tempered) and it breaks into very small, less injurious pieces if compromised.

There is no benefit to radiant heat or UV reductions with tempered glass so it will require tinting.

Low-e on the other hand will reduce the radiant heat from the sun and in most cases, by more than 200% as compared to clear glass.

Low-e will also have a slight tint to it as a result of the coating but what is proper amount for you depends on your preferences.

    Bookmark   July 11, 2012 at 10:12PM
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Wow, thank you for the responses. My window is very large, and only replacing the glass, and it is double paned. What is Low E2? To me tint/coating is important, as it is a large living room window (approx 92x58). If the low e coating is not sufficient, is it common to have a film applied to the inside as well? Also when looking out, is it clear? I have read about a greenish color to the glass. Don't really care if it is on the outside. Thank you!

    Bookmark   July 12, 2012 at 2:04PM
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Low E2 is 2 coats of Low E. I just think 2 when dealing with double pain, but 366 glass in double pain will have 3 coats, and that is what I think you should get.

If the window is that large, it would be advisable to go with tempered.

The question is, do you want an actual tint. If for privacy you do, get a bronze tint. If not, 366 will protect you from the intense UV almost completely. Argon fill would also be advisable.

I don't recommend tint film on double pane home windows. It has to be applied to the interior, and it always causes failures in the unit. Either get tinted glass, or 366 glass to block out the UV heat. Tempered should not be a problem with either one. It's really not much more complicated than that.

I'm not an authority on glass. But what you're looking at is pretty basic stuff.

    Bookmark   July 12, 2012 at 7:53PM
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Using tempered glass will help protect your window from heat related stress breakage - I suspect that the window company that suggested tempered glass was considering the possibilty of an after market window film and they realized that you would need tempered glass to avoid future heat-related stress problems.

Using LowE is not an option, it is a necessity in your (or any other) environment. The primary consideration being what LowE coating to use in what environment.

As mentioned, you do not need supplemental interior window film when you have a LowE coating...in fact, once again, it would be a very bad idea to do so when using annealed (non tempered) glass because of potential heat stress problems.

As I mentioned in my earlier post, it is very unlikely that you will ever notice a color shift under normal viewing conditions when using a LowE coating. It really is a non-issue - LowE coated windows do not have a noticeable tint in transmittance (when looking thru the glass).

Since your window faces south you should consider a couple different options (in addition to the solarban 60) when it comes to LowE coatings.

Solarban 60 is a "LowE2" coating. That means that it has two layers of silver in the coating. Silver is the operative element in a LowE coating. LowE2 is considered to be a moderate solar heat gain coating.

A LowE3 coating (LoE-366 mentioned earlier as an example) has three layers of silver in the coating and is considered to be a low solar heat gain coating - meaning very little solar heat will get thru the glass - summer or winter.

In addition to the two and three silver layer coatings, there are also coatings that are considered to be high solar heat gain (a couple different types, including single-silver layer coatings).

In a heating-dominated environment, a high solar heat gain coating on south-facing glass may be your best option because in the winter it is going to allow some very welcome heat into your home.

The downside of course is that it will allow more summer solar heat gain than will either of the other two options.

Solarban 60, as a moderate solar heat gain coating, will allow less solar heat gain in both winter and summer...but it will still allow some winter heat gain which is usually very welcome.

How high up are you?

    Bookmark   July 12, 2012 at 9:57PM
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It is great corresponding with people so knowledgable on this subject. I'm really learning a lot about glass. We are at about 7200 feet. If I am understanding correctly, it sounds like I should go with tempered low e2 or 366 solarban 60 without film.

    Bookmark   July 13, 2012 at 1:31AM
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Yes, you are hearing correctly. Films are only useful on older windows. I would never recommend the use of film on regular strength, double pane glass. I would suggest you find a local contractor who is knowledgable about the proper use of moderate and low solar gain glass. It might be that a combination of the 2 on different elevations would be the best way to go.

    Bookmark   July 13, 2012 at 6:28AM
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You guys are awesome!! Thank you so much for all your knowledge.

    Bookmark   July 13, 2012 at 10:44AM
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You guys are awesome!! Thank you so much for all your knowledge.

    Bookmark   July 13, 2012 at 12:24PM
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Make sure the company you buy the glass from knows that it's being installed at 7200 ft. It will probably therefore have capillaries for that altitude.

    Bookmark   July 14, 2012 at 9:43PM
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