I live at 7000 ft in Flagstaff Arizona and found I had to deal with issue even if it doesn't get as hot as Phoenix. Our solution was to put a shade canopy over our southern exposure windows which includes my sewing room. I use a small portable AC unit now for about 2-3 weeks out of the summer. The canopies literally cut our cooling bills by 40% now. We use a open mesh weave from a landscape company, made our own heavey duty metal frames (get winds gust up to 80mph up here at times) and have used them now for 7 years.