I installed solar screens on my house. I remove them in the winter to allow the warm sun in. The difference is very easily noticed. there is a chair in front of one of our windows, if the screens are not in it is too hot to sit in the chair. With the screens in place I can sit there and enjoy my dinner no problem.
The majority of sunlight striking an unprotected glass window passes through into the home, and a small percentage is reflected. Solar screens dramatically reduce the amount of sunlight striking the window. Most of the sun's heat is absorbed or reflected by the screen and carried away by convective air currents created by the warm screen. In midsummer as much as 230 BTUs can fall on each unprotected square foot of glass.
With SunTex installed, up to 90% of the sun's heat and glare is reflected, absorbed and dissipated before it strikes the window