"houses are now built with very little regard to insulation"

I find that hard to believe. Where I live the local muni delegates to a state wide "uniform dwelling building code" I googled it for laughs and the minimum ceiling insulation as of the '09 revision was R-49 which is about 14 inches of fiberglass.

My concrete block basement walls met code 50 years ago at about R-2 insulation value, as of '09 the mandatory minimum for new basement walls is R-15, OK then..

The biggest problem I see with post-AC era houses like mine is very poor cross ventilation. I must run the AC when its 60 degrees outside because the windows are not oriented for cross ventilation so I will roast alive at 85 degrees indoors when its 60 outside without AC.