I am building an energy-efficient home in Williamsburg, VA and am interested in maximizing efficiency in the type of windows I am installing. The problem I encounter when shop-ping for windows is that there doesn't seem to be an indus-try standard to compare brands for heat, cold, wind resist-ance, etc. It makes it very hard to compare differences in materials used, is low-E the same standard for all brands who sell low-E?, the types of seals used, etc. I want to use a product which will serve my "energy-efficient" needs and be reasonable to purchase. Do you know of any compari-sons accross brands? Maybe something like a CONSUMER REPORTS-type comparison for windows.