How much saving from new insulating windows?
If you are going from a single pane, older window to a very efficient double or triple pane window you will have better results than if you have fairly good windows and go to more efficient ones. I live in Western Oregon where we have pretty mild winters and summers so the savings will be less than a house in a region with severe cold & heat. I used to live in Central Washington where the winters get very cold and the summers are very hot. Our house was 3 stories and 70% windows on 2 sides. The windows were single pane. By going to top of the line windows we were able to cut our heating and cooling bills by over 30% during the coldest and hottest months.
