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bestany

Light transmittance

6 years ago
last modified: 6 years ago

Hello,



My Marvin Elevate window install commenced today, which is awesome. I chose LowE 3 glass for extra UV filtering, but here’s my question... The glass is labeled LowE 366 which I understood to mean .66 or 66% visible light transmittance, but the Marvin label shows light transmittance as .49. Why the discrepancy? They are double pane.

Thanks

Comments (2)

  • PRO
    6 years ago

    The 66 number refers to just the glass coating. In this case, the Cardinal Low-366 is a three layer process that allows for 66% of the visible light transmittance (normal double pane float glass is about 82% as a comparison)...but this number is relative just to the glass.


    When you look at an NFRC rating, it is giving you the total unit VT numbers so what you are seeing is the decrease in VT because of light transmission losses due to frame and sash.


    When they do a VT rating, it is on the unit and they measure from Tip to Tip of the frame.


    Install looks good so far.

  • 6 years ago

    Okay, that makes more sense. Thank you for the info!


    The hue of the glass is taking me a hot minute to get used to, so I’m nervous to make sure things are as they should be. I have Andersen LowE 4 Smartsun glass in an addition on the back of the house (that was a sash-only replacement four years ago). I heard that both brands used Cardinal glass, and with nearly the same specs I assumed the glass would look the same. To me the new Marvins look more green 🤷‍♀️ .



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