I recently replaced a broken small window with Lexan polycarbonate. Lexan is reported to yellow after 10 years. How bad is this likely to become, how quickly -- will I have to change the window again in 10 years to be able to see clearly through it?

  • It turns out the utility company where I live no longer manually reads the meter, but have other smarter ways of figuring out my usage. It still might be interesting to know how the transparency of Lexan degrades over time and if you can put anything behind Lexan and expect to be able to read it indefinitely. Apr 13 '16 at 1:17
  • It's true that utility companies rely on wireless technology to read meters now, however, like all technology, it sometimes fails. In this situation, you might start seeing "estimated" usage on your bill which may or may not be accurate, which may then result in you or the utility desiring a manual read. You would want this to be possible.
    – Jax
    Jul 10 '16 at 19:53

About 10 years in Florida, if given an anti-UV treatment. Here is an old GE technical report which gives details http://www.bristolite.com/interfaces/media/Tech%20Report%20GE%20Lexan%20Polycarbonate%2010%20Year%20Aging.pdf


A photo of the situation would help. But if you are "repairing" the meter itself then the better advice would be that you get the meter replaced instead. There could be some concerns raised with tampering with the meter if its seals are broken.

On the other hand if this "window" is a separate thing from the meter then why mess with Lexan if there is a clouding concern. Just replace it with some good quality thick glass will stay clear for a long time.

  • 1
    Thanks for the info. The window is a separate window not part of the gas meter itself. I'd prefer Lexan because other people are frequently around that window and they might break it again. Found out that the gas company doesn't manually check those meters so no problem. Still might be useful for others to know how Lexan transparency degrades over time. Apr 13 '16 at 1:19

It depends on climate and whether the Lexan was treated or coated for UV exposure. There are greenhouses that go far more than 10 years and they aren't yellow. For untreated Lexan the yellow is on the surface and can be polished off. My generic Lexan window on my chicken coop is about 5 years old and not yellowed that I can see. My climate is very sunny for 4 months of the summer and mostly cloudy the rest of the year, 48 degrees latitude.

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