Energy Star requires that Low E Glass be used in all residential window installations. They are usually fairly thin framed at 2 3/8 to 2 3/4' thick from inside to outside which is almost one inch thinner than a mid ranged unit. Cheap windows are usually aluminum or vinyl. Even when you have your builder upgrade their window offering it usually is an improved version of the builders grade, but it is seldom up to the quality of a mid range replacement window. Builders only warrantee their home for one year and a window that lasts longer than that is a perceived waste of money to that builder. Builders Grade windows are a prime example.
It's a fact that there are cheap windows.
