If privacy is not your utmost concern but effective heat rejection is, Buy Decorative Film's EXTERIOR Silver 35 High Heat Rejection window film would be your choice. As the name suggests, the Exterior Silver 35 is applied on the outside of the window, working to reject heat before it even passes through your windows. With a mild, silver tint, the Exterior Silver 35 adds some shade to your window, but it is one of the lighter options you can pick from that will provide very good heat rejection. This heat rejection film is a preferred choice for dual-pane windows since it is applied on the outside, so if you have dual-pane windows but want high heat rejection, the Exterior Silver 35 would suit your needs.
Since the film is exposed to the conditions outside, the edges of the installed film should be sealed with silicone window caulking after the film has fully dried.