Talk:Low emissivity

message: it sounded like the only sensible thing to do
BUT
here in southern Spain, our low e- glass does not seem to perform to well
if fact - it does so badly, that I started doubting the glass IS LOW E...
?anybody knows how one can tell weather the glass IS what the sticker that came on it syas?
thanx
YOU SHOULD BE ABLE TO HOLD A LIGHTER UP TO THE GLASS AND ON THE CLEAR SIDE YOU SHOULD SEE 2 REFLECTIONS AND ON THE LOW-E SIDE OF THE GLASS YOU SHOULD SEE 4 REFLECTIONS.
"Coating a glass surface with a low-emittance material reflects a significant amount of this radiant heat, thus lowering the total heat flow through the window."
- Shouldn't it be the other way around? The pure definition of Low-emissivity as its name suggests, is that its ability to emit energy is low. Because of this inability to lose energy, it inevitably reflects radiant heat.
"Low-E coatings are transparent to visible light, and opaque to infrared radiation. Different types of Low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain."
Low-E coatings are opaque to long-infrared rather than near-infrared. The latter is the IR from the sun while the former is converted from other wavelengths like UV, Visible Light, Near-Infrared, etc.
The reason why Low-E coatings are now able to allow for moderate- or low-solar heat gain is because of solar control coatings that have been added to the glass or coated onto IGUs. 
Soft-coat or Sputtered Low-E Coatings must be placed within IGUs. Pyrolytic or Hard-coat Low-E can be on single-pane (monolithic) but its effectiveness cannot match up to the sputtered ones. Also, for pyrolytic Low-E glass to achieve low-solar heat gain, the glass can be tinted. Again, it is not the Low-E coating which reduces heat. This is a gross misunderstanding in the glazing industry.
So in essence, Low-E coatings are primarily for heat retention (for winter in temperate countries or heating environments), and NOT for keeping out the heat from the sun. That probably explains why your Low-E window in Southern Spain is not working. --NVX 02:23, 19 July 2007 (UTC)
thread_title:  Some old discussions 

message: What specific materials are utilized in low e coatings? I'll attempt to ascertain. LorenzoB (talk) 05:39, 20 November 2008 (UTC)
replies: text: Soft coat Low - e uses silver, Hard coat uses tinHschlarb (talk) 02:46, 11 December 2008 (UTC)
thread_title: Material

message: Looks like the lead paragraph was lifted verbatim from http://www.efficientwindows.org/lowe.cfm. Archive.org proves that the text there predates the article here.  I am going to remove the lead and replace it with a rudimentary lead. --Justallofthem (talk) 20:04, 4 May 2009 (UTC)
thread_title:  Plagiarism 

message: Why is the name of this article Low-emissivity, with Low-emittance the bolded name in the intro, and no mention of "low-emissivity" in article, and why is Low-emittance red?  What about low emittance, low emissivity, etc.?  Why is the "E" uppercase, and why isn't it italicized (it should be e).  Why isn't the epsilon symbol mentioned?  Gene Nygaard (talk) 01:35, 5 January 2010 (UTC)
thread_title: Naming goofiness, etc.

message: This article claims that emissivity + reflectivity total 1, but Thermal Radiation claims you must also add transmittance.  I believe the latter is correct... am I missing something? --Colanderman (talk) 04:22, 6 August 2010 (UTC)
thread_title:  What about transmittance? 

message: There is a   with reason=the adjective at this place in the sentence makes no sense to me; what is the intended meaning?.  Light coming in must be transmitted, reflected, or absorbed. For an opaque substance, it is either absorbed or reflected. In symbolic form, emissivity is e or ε. For an opaque substance, it might be εo. The adjective then comes after the noun, as that is where the subscript is written. Maybe this helps. Gah4 (talk) 07:51, 3 January 2024 (UTC)
thread_title:  emissivity opaque