I remember the first place I lived with my mom, dad, and brother.  It was an old one room apartment.  In the winter it was freezing and we bundled up like we were going outside.  The old single pane windows let the cold in.  We didn’t use the heater much as that meant less money for food. Most of the year I’m more concerned about not being hot so I purchased windows with the highest rating for blocking out the sun.  The government ratings call it SHGC or solar heat gain coefficient.  My windows were rated to block out 81% of the sun’s heat which is pretty good.  It’s only…