Not sure on whether it reduces the heat inside the trailer but it reduces some of the sun coming through which I would think, some of the heat. The awnings seem to do more for heat reduction through shading in our limited experience with it so far.
We installed the solar screen (85%) in black on our AS last month but still have not camped in it yet except spending one night in the driveway which is somewhat shaded with trees. We do like the look and the fact that people can't see in during the day but we can see out great. At night, with lights on, you can see inside so curtains will be used in ours. Photos:
Installing the screen:
Looking from inside out:
Looking outside in: