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366 Green Tint Concerns

BonnieMatheney | Posted in General Questions on

We toured a unit that has Cardinal 366 double pane glass windows and there were reflections of green inside the unit when the sun was shining.  See pics.  I’ve also included a picture from the outside and do not like the green windows from the exterior view either.  There is also a pic where the window is opened and you can see the difference in the white snow.

I also have a sample of this glass and when the sun came inside my unit I took a pic where you can see how it cast green on a light colored rug and cream colored tree skirt. 

This has me very concerned because the building I live in wants to change our windows to this same 366 glass.  This is on top of the fact that our large balcony sliders in the same room won’t be replaced for 15 years and so we will have 366 windows next to clear glass.

We are in Chicago so why would anyone want green windows when we have 176 cloudy days a year and very short days in the winter?  Why would you not want to maximize natural light and not have a tint?

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Replies

    1. BonnieMatheney | | #4

      That was focused primarily on the difference in the same room. We don't want 366 glass even if the balconies were getting replaced too. And since I asked that question I saw what 366 glass looks like from the interior and don't like it. I don't want to see green at all. It was very distracting. So I wanted to update the question to understand what else is out there that won't make us have green shining in our units and distorting our beautiful views versus just focusing on the difference. Sorry to be confusing.

  1. Expert Member
    BILL WICHERS | | #2

    Most normal glass has a bit of a green tint to it from the iron. This is why Starphire glass exists: it's very clear, and doesn't have the green tint that normal soda lime glass has. You tend to see Starphire glass used in thicker glazing though, such as 1/2" thick panes (where a glass pane is 1/2" or more thick, not the entire IGU). The easiest place I know of to see the difference is with the edge of a glass aquarium: regular glass looks dark green, starphire is much more clear, maybe a very slight blue/gray tint.

    The higher level low-E coatings like 366 all have a slight tint to them. The coating with the least noticeable tint is 180. Most people don't really notice much difference unless they have two very different coatings next to each other to compare, which you seem to in a few cases. Personally, I wouldn't really find a shadow/reflection with a tint objectionable, I'd be much more concerned with the view THROUGH the window.

    I recall you asking similar questions on here recently. You're likely to notice the difference between the sliders and the fixed windows, due to the vary different tints, but because of the way the wall is broken up, it won't be as bad as it would be with the different tints right next to each other. I think you'll end up finding it to not be too objectionable, although you will notice the 366 glass to be a bit darker and with a slight tint compared to the older glass.

    Also, if this is part of a major reglazing project on a large multiunit building, are you really going to be able to offer much input to the building owners? Is your concern more just a "how is this going to look" type of question, or are you looking for alternatives to present at something like a tenant meeting?

    Bill

  2. BonnieMatheney | | #3

    Yes, a large group of residents want to encourage the Board not to choose the 366 glass. We bought our units for the beautiful clear views and want to maintain as much natural light as we can and meet Chicago Energy Requirements. We were planning to ask for 180 glass since we understand that does not have a noticeable tint. You are correct and looking through is the biggest concern and when white snow doesn't look white that is a problem. I have not heard of Starphire before. I will need to look that up. Thank you for that suggestion!

    1. Expert Member
      BILL WICHERS | | #5

      Starphire glass is *significantly* more expensive than "regular" glass. Keep that in mind.

      If you want minimal tint, 180 is your best bet. As you go up in number, the coatings get darker and more noticeably tinted in terms of a color (a "gray" tint isn't really any different than just being "darker", so I don't consider "darker" a tint here). The biggest difference between 180 and 366 is SHGC, the amount of heat gained from sun coming in. Note that in the winter, sun coming in actually helps you heat your space a little, but in the summer, that sunlight is increasing the cooling load on the building. Any of these coatings is going to perform significantly better than non-coated clear glass though, for both insulating value in the winter (U factor), and solar heat gain in the summer (SHGC)

      Since you'll probably need to present at your meeting, I recommend you review Cardinal's Technical Glass Guide (https://www.cardinalcorp.com/wp-content/uploads/2023/03/TGG_V3.0_Final_6-15-2021.pdf), which has all kinds of information on all of their coatings and IGUs. There is a LOT of data in there, from the manufacturer of the glass, and comparison information. I recommend especially the U value comparisons on page 14, and the SHGC comparisons on page 21.

      In your commercial building, you're probably using IGUs with 1/4" thick glass panes and 1/2" spacing.

      Bill

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