I got this from d-90 source so go to the site if you want to know the original post. I think this would be a benefit to us who want to tint our windows
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Cheap window tint blocks light, but not much heat. Most heat from the sun comes from the near-infared spectrum (~52%). Some from the visible spectrum--which you do NOT want to block 'cause you gotta see out--and a little from UV. So the glass or applied film or coating must block the IR. Otherwise window tint is nothing more than darkening your windows making them hard to see out. Windows, window film & coatings should be rated. Check for these ratings before buying to be sure your time and money will work for you yet not hurt your eyes.
Tvis= visible transmittance. % of visible light that makes it through. Want high, like >70%.
SC=Shading coefficient (similar is SHGC). ratio of solar transmission to the tranmission through a 1/8" clear glass. Want this low, as this will keep out solar heat load.
Ke=emissivity or visible light transmission while rejecting solar heat--you want this number high to allow light in and easy to see out of at night. near 2 is great.
r or u=insulative value--temp. diff. b/w two sides of a window. Not as important as solar heat load control, as above.
Cheap tint is of little to no help to keep heat out. Good tint or coatings should list these values.
KC
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As for me, solar guard is relatively good one
3 comments:
Just another Series 3 enthusiast checking in and saying HI from South Africa.. :-)
Oh hi Michelle (sounds like a French name to me.. :-) ) it is glad to "meet" another land rover enthusiast far away from here.
Cheers
Window tinting is very effective for home, business or automotive use. And you are correct that the infrared wavelengths do carry a great deal of the "heat energy". But you also have to consider other factors as well; pricing, glare, privacy, appearance, ect. So its never as cut and dried as just saying, okay, tint my windows.
The newer, and considerably more expensive spectrally selective window films filter out a great deal of the infrared band while leaving the majority of the visible light. For some this is an excellent option. But professionally installed this is expensive film, maybe $12 dollars US and up per square foot of glass, and you will be hard pressed to find it for self installation. This product is normally reserved for the largest installation pro companies and best customers. In addition, in my experience, most people who have exceptionally "hot" windows, also have very bright windows, creating a lot of glare or simply excessive light. The solution is to choose a light to medium tinted film that blocks the heat but also protects from the glare and UV as well.
Lastly, its my experience that once the film is installed, most people felt that they should have gone darker; not for additional heat abatement necessarily, but for more glare control. Everyone is different of course. But I can tell you that even with most of the darkest tints there is still a considerable amount of light entering the home. Again, it does depend on personal preference. I have just started a blog on home energy control issues. Feel free to stop by some time.
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