It is noticeable. Yes.

Windows on Washington, thank you! That is good to know. Will it make that much of a difference since we mostly experience cold in Seattle and not a lot of heat? Are there any options such as a one coat-process, instead of two that would look more similar to the clear glass? Replacing these windows is giving me a headache!

Can I buy a low e 179 window?

https://www.cardinalcorp.com/technology/reference/loe-performance-stats/

oberon476, I live in Seattle, WA and the windows are north and south facing. I am so worried about blocking light here as it is dreary for so much of the year! Do you think the LoE 179 would work? I really appreciate your response!

Jan, thanks and I totally missed the Seattle in your original post...

I think LoE 180 (179 has been discontinued) might be the ideal solution for you.

The U-factor would be slightly higher (worse) than if using either 272 or 366, but Seattle is a mild climate where the difference is minimal.

LoE 180 is intended for high solar heat gain applications and because of that it's usually installed on glass surface 3, but in your case I would request it on surface 2. Surface 2 versus surface 3 would result in less solar heat gain but has no effect to the U-factor.

In your climate I think that blocking a bit more summer solar heat gain matters a little more than allowing more in winter since winter doesn't see much sun. Really more a personal observation than measured data, so ultimately your call.

And visually you won't be able to tell the difference between clear glass and glass coated with 180.

Who is the window company??

It is Lindsay Windows.

I know the name, but not details about them.

Did they tell you that they offer LoE 180?

There is no reason to have LoE-366 coating in Seattle. Furthermore, it is usually an upcharge. To be clear, are you saying your installer's quote was for Low-E 366 glass? Low-E 270 is almost always standard with no upcharge. Make sure what upcharges in the price for your project you might not even know about. I am concerned about your difficulty with your installer not answering your questions. Remember, you could have the best windows in the universe, and if the installer isn't good, those windows won't be good. I advise you to stop with him, and seek another installer.

No, I am going to call my window guy in a minute. I think I am making him crazy. I just do not want completely mismatched windows from downstairs to upstairs and I do not want a green tint. Can you please explain your reasoning for changing the surface? I have been doing so much research on these windows that I think I am losing it. I think it is called "paralysis by analysis"! We are spending $5600 on four windows, so I want to get it right. I really, really appreciate your advice!! I would have thought the salesman would have told me some of this, but he does not seem terribly knowledgeable. I wouldn't have even noticed or known anything about the low e 366 had I not mentioned it to the older gentleman who came out to measure the windows!

M Miller, this is a company that received exceptionally good reviews on Yelp. I think it is basically the salesperson who is as fault for just "giving" me the low e 366 windows without even telling me. Lucky I noticed it on the contract the day the measuring gentleman came out and I asked him about it. I am stuck with this company since I have already signed the contract aren't I? I wish I could back out now and go with someone else as I really don't want to give them my business! But, we have told them to hold off on ordering the windows until we get this cleared up. Thank you so much for your advice! Since you seem very knowledgeable, do you think the 272 windows would look terribly green on top of clear, double paned ones on the bottom floor? Honestly, I never dreamed purchasing windows would be so confusing!