On a scale of 1 to 10 with one being best my windows are 13's. Caddy to Nash Rambler?? Nash Rambler.
Unfortunately this problem is man made. Made by this man! lol. I purchased the cheapest windows available and they are single pane with nothing to protect from the elements. In addition I increased the size of the home considerably which altered the original concept of heating and A/C needs. I went from 3 ton to 6 ton a/c and heat strips to compensate for the changes. Unfortunately the windows allow all the elements in to defeat the adjustments. I can control the environment but costs have escalated from 150/160 a month to in excess of 500 a month.
I will reinstall the solar sheeting again and that will help some. Might form a secondary window frame with additional insulation of some nature to help.