I like the reflective mylar that you can install yourself with a
little practice, or have installed. OSH caries it in different
widths. It comes in Bronz, Grey and silver, cuts ultraviolet about %70
and heat measurably. Did my double pane windows over ten years ago and
it is still holding well. Just remember to be gentle when cleaning it
as not to scratch, a squeegee is best with a little mild detergent.