IMO, they are good if taken care of, my house that was built a few years ago had them installed, only problem was.... They are plastic more or less... A SMALL lightweight AC unit, ended up causing the tracks to bow out, and now the window doesnt shut completly, it has to be forced closed using the locks on the window, but other wise, if you don't need a window ac unit then they are great at keeping heat/cold in and out.