We have a big expanse of east facing windows that catch a lot of morning sun. In the summer this results in a lot of unwanted heat gain, and makes the inside temperature increase dramatically when the sun in on these windows. It also results in a lot of glare.
We tried a set of these exterior roll up shades. The shades are made out of a shade cloth like material. They block a fairly large percentage of the gain, and they do it on the outside where it is much more effective. The shades still allow a pretty nice view even when they are down -- its a bit filtered, but nice. They definitely make a significant difference on both the heat gain and the glare.
The combination of these shades and a few other changes has made the house much more comfortable without the need for AC.
We bought ours at the local big box hardware. I think that that the brand was Coolaroo. They come in a variety of widths and lengths, but none matched our windows. I was able to buy ones that were a few inches too wide and cut the width down. This was fairly easy, but requires a hacksaw to cut the metal roller. The shade material cuts nicely and cleanly with a scissors.
The shades have little anchors at the bottom for winds. Ours have been through several episodes of high winds with no damage.
Gary July 24, 2009