I live in the midwest with cold winters and would like an energy efficient window that will last for 20 years. Since I have an Arts and Crafts style home I would like windows with wood on the inside. I have been looking at Marvin aluminum clad wood windows and Mavin Infinity fiberglass with wood veneer inside. The aluminum clad are less expensive but I read one posting that said the argon dissipates much faster with this type window. Does anyone know if that is true?