These windows ROT under the aluminum especially on the bottom of the actual window. Ours are 12 years old and the first one that rotted out was 5 years ago. It is not incorrect installation, it is a bad design that allows condensation to form UNDER the aluminum cladding. Lack of a sealant in the mitered corners contributes to moisture problem. Replacing the glass portion now costs more than we paid for the entire window originally. NOT to mention install charges. A huge Marvin window with aluminum clad exterior installed a couple years earlier in the same home does not have moisture problems. Since windows are a major improvement in a home, I would NOT recommend Pella.