# Window UV protection



## Lee in MO (Mar 17, 2007)

Does anyone know if there is a device that can sense the light rays from a window to determine if the window is UV treated?


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## glennjanie (Mar 17, 2007)

Welcome to the Forum Lee:
I understand all glass will stop UV, it is the infrared that passes through. I had been taught that in high school but it became real to me when I bought prescription glasses with lenses that automatically darken in UV light. At the time I was doing a lot of driving and needed the dark glasses. The glasses would not turn while I was in the truck because they got no UV.
Glenn


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## Lee in MO (Mar 20, 2007)

We have some skylights that are not shaded and let in a lot of sunlight during the summer.  I'm a little concerned about fading of the furniture if the glass is not treated properly but I don't know how to tell.


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## glennjanie (Mar 21, 2007)

Regular automotive window tint will repel the infrared rays which do most of the fading.
Glenn


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## Oberon (Mar 30, 2007)

Is the skylight glass or plastic?

If the skylight glazing is plastic (either polycarbonate or acrylic), then it likely has a UV inhibitor that was included when the plastic was made, and that will prevent UV rays from passing thru the material.  

The UV inhibitor is included in the plastic formulation to prevent the UV rays from the sun to degrade and eventually destroy the plastic.  Both acrylics and polycarbonates are highly susceptible to UV damage when manufactured without the UV inhibitors.

If the skylight glazing is glass, then it is likely either tempered or laminated.  If the skylight has laminated glass in its construction, then better than 99% of the UV rays are being blocked by the interlayer material used in manufacturing the glazing.  This is similar to the UV inhibitors used in the manufacture of the plastic glazings.

If the skylight is glazed using tempered glass then it has no specific UV protection.  While ordinary glass is opaque to UVB (which causes sunburn), it is transparent to UVA which is the UV that gives folks their nice golden tan (and is also likely the primary contributor to skin-cancer) and UVA is also the primary contributor to furniture and carpeting fading.  

The glass in the skylight might have a LowE coating which will cut down on the UVA that passes thru the glass.  The darker the coating, the greater the ability of the glazing to protect against fading damage.  While UVA is the greater part of light-related fading problem, visible light also has some affect as well - it is a wavelength dependent issue.  

There is equipment to measure how much UV is coming thru your windows, but as mentioned in a previous post it is expensive and not generally something to which a typical homeowner would have ready access.


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