Opaque Walls Idea That Lets All Air In And Out

.

I bought one of these the other day for my bedroom window, you can change color by going to the top scroll menu of the two, and selecting: "Vit", and if you click the image, you can see it larger.

http://www.ikea.com/webapp/wcs/store...umber=80049516

I tried it out against my grow room and it didn't let out any light at all.
They're made from 100% cotton, but one side is treated with acryl, making that side slightly shiny.
I'm thinking of replacing the door to my growroom with one of these, since air passed easily in and out without letting light through, and my temp dropped several degrees.

My one is dark blue, so I don't think that would reflect the light, but I'm wondering about the white one? I think the white ones are just as opaque, since they're treated on one side.

What do you wonderful people think of this idea?

Or maybe it could be used for flowering in the veg room?

.

.

Better image:

yo dude they slang them things at hd too next to or behind the miniblinds