You need to learn about their ratings and how they compare Consumer
Reports has an old test done of apx 23 windows, www.energystar.gov
will help. Just an example there are 2 or three types of LowE coatings
avalaible, depending on your area will determine what you need, Southern
areas usualy want to block as much solar increase as they can. You need
to know all the ratings to compare them. Anderson is a good product, but
there are others.