We have only one window that faces the south and it's for our den (aka: my "man cave"). My wife doesn't like coming into that room because, between the sunlight and my hot computer, the room is always 10 degrees hotter than any other room in the house. We went to the hurricane preparedness clinic a couple of weeks ago (as it's our first year here) and ran into a company called Underglass. I got them to put in 3M PR 50 film on the window for the den. That's the "medium dark" film and I don't find it all that dark. It's supposed to reject 97% of infrared and 99.9% of ultraviolet. What it has for sure done is dropped the temperature of the room by 10 degrees. That film clearly works. The young lady who installed it did so quickly and precisely, was polite and answered any questions we had and left no mess behind. If I had more windows that needed it, I'd do it again and probably with them.

We have installed 3M film on the inside and outside of all of our windows. Makes a big difference.

They install the film on the inside of your windows.