Perception of light, much like temperature, is a very personal experience. Some are more sensitive to light than others.
Allow me to address your points in order:
Whether 10% is noticeable is entirely dependent on the person. For the record, 10% is about the same amount that you loose through a single pane of glass in this case so lets make the point to keep that in perspective.
VT of a single lite of CLEAR glass is 90%
VT of dual pane unit, CLEAR glass, is 82%
I am not "motivated" to tell homeowner's how great it is. It is the technology of today and is the most cost effective option impacting efficiency. I suppose you could look at triple pane or other staged clear glass assemblies for efficiency in lieu of Low-e, but each of those additional pane is costing you about another 10% in VT. The conundrum remains the same.
I think you might be shooting the messenger here. I am not trying to "sell" windows here as much as I am trying to inform folks. Building Code in most of the country will require a window with Low-e so if you have a problem with Code, I suggest you take it up with the government.
My point has been that there are definitively different types of Low-e and if you are noting a huge offset in light, it is likely that you got the wrong Low-e either for you home, you climate, or at a minimum...your preference. That is a fault of the contractor or the selection process on some level.
If you would like to let us know what window you got and post a picture of the NFRC label (or serial number label), I can tell you what Low-e you got and where the problem might be. If it is just a single window, you might be able to swap the sashes for a proper Low-e or for just clear glass.
Until you have provided that information, we can't really know what the "truth" of the situation really is.
My comment to David is the same as it would be to your statement. The only one that is incorrectly categorical is the one that lacks any data or facts to support it. To say that Low-e is terrible and makes the house dark is totally based in opinion and while it may be that person's truth, without any background information...it is severely lacking.
For the record, I am not doubting what you are feeling, but I haven't the slightest clue about what Low-e you got and what window you are talking about. The facts are that Low-e, when PROPERLY specified, should only be about a 10% offset. If someone that was specifying the window doesn't know the specs or the details...you may have gotten a very dark window. That isn't the fault of Low-e as much as it is the fault of the person ordering the window.
The categorical statement that I am making is based on data. We have installed 10's of thousands of windows at this point and the number of client complaints is infinitesimally small. Granted, we are specifying the right Low-e for our climate, but the number of complaints is less than 5 in 15 years. I think that is a bit more data driven sample and comment.
If you want to categorize the 10,000+ posts that I have on Houzz and other forums trying to help folks as "selling" windows, so be it. I guess you haven't seen the countless posts where I have tried to help folks (even when that means steering them away from buying a product that they thought they needed). If this is "selling" windows, this is a less than effective way to do it.
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