What percentage of the sun's rays are blocked?
502730
I would say about 75-80%. It's enough to make a huge difference. Make sure you have strong anchor points if it gets windy. Use rope to attach the sail to the anchor points, as the rope will absorb some of the energy in strong winds.
502731
I will say 99.9% of the sun's rays are block. We have complete shade. I have never gotten sunburn under the shade sail.
502732
it gives a pretty good shade under it but it is not too big so if you buy only one then is only a small triangle that will block the sun
472030
I think it may depend on the color you chose. I bought the wheat and covered a pergola roof and made curtains with it. At night you can see a few stars and the moon. during the day the sun does shine through but it blocks enough that it doesn't blind you if you look at it. I've heard others say that the darker colors will provide more shade but depending on the grade you purchase it my not provide as much uv protection. The curtains have folds in them so they block more light. However I really like being able to pull them flat and see the sunset in the evening. If you want total block, Coolaroo won't do it alone. You'll probably need to use some sort of backing material. You could double the layers and they might be enough with some of the darker colors but not with the wheat. Hope this helps.
1703167
It is dark and you can't see in unless a light is on. It does cut down on the glare from the sun.
738812
I'm sorry, I can't answer that I have tinted windows. I never get direct sunlight on the unit!
1884529
I brought for preventing tree debris falling on the car, not sure about 100 degrees sun blocking.
2187705
The percent refers to how much light is blocked. These block 50% or half of the light, while the other one your looking at only blocks 38%, about a third. The smaller percent, the lighter the shade.
607899
You can see through it - It will block the sun like shade it but not completely.
794864
Website says blocks UV rays from up to 400 nanometers? Here's the link. http://www.bolle.com/technology/goggle/technology
35508
Somewhere in the description of this shade it mentions that though it blocks (I believe) 80-85% of the sunlight, it is still porous. If it were a pelting rain against the shade I am sure that the rain would not be totally blocked but would be atomized. (We normally try to roll the shades up when it is raining to help prevent the chances of moisture being trapped and creating mold.)
1307856
im sorry but i returned mine back because it didnt block the sun..my daughter complained about the sun..
2046266
I'm sorry...I don't know the %. My screens are very dark, almost black. But I can still see out of them during the day and no one can see in. If you have a light on @ night...someone can see in.
385375
My thought was yes. UVC is a short wavelength and that is why it is blocked by our atmosphere. So it is easily blocked by glasses and probably plastic as well, especially plastic that we know blocks UVA and UVB rays. Here something from Wikipedia: Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.So with resonable confidence yes they block UVC, which is what germicidal lamps put out. Watch out for your exposed skin though. My thought was yes. UVC is a short wavelength and that is why it is blocked by our atmosphere. So it is easily blocked by glasses and probably plastic as well, especially plastic that we know blocks UVA and UVB rays. Here something from Wikipedia: Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.So with resonable confidence yes... » Read More My thought was yes. UVC is a short wavelength and that is why it is blocked by our atmosphere. So it is easily blocked by glasses and probably plastic as well, especially plastic that we know blocks UVA and UVB rays. Here something from Wikipedia: Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.So with resonable confidence yes they block UVC, which is what germicidal lamps put out. Watch out for your exposed skin though. « Show Less
678548
This is specifically only for viewing the sun. It blocks a very high percentage of light and only allows a narrow band to get through. This is what makes this telescope great for viewing details on a very bright object such as the sun.
750828
The sun zapper attaches to the visor. Therefore, it only moves up and down. Effectively blocks sun much of the time.
1517040
It depends on your definition of "some". Mostly it block the view -- very well -- shapes can be seen but not detail and although the windows I covered are under a full awning, I have noticed no reduction in sunlight.
38545
It is an excellent diffuser of sunlight but not an absolute blocker. I think it should sufficiently reduce the glare from sunlight.
17082
It would work great as a privacy screen. You might be able to see shadows through it but that's all. It really does block almost all the sun. We use it on a screened in deck to block the afternoon sun.