I am having 19 of our windows replaced as they are the original windows in a 90 yr. old house. I have heard both positive and negative about having an foam insulation in the window from different salesmen. Can anybody give me any guidance on which is better? I have heard that the dead space is actually a better insulator than the foam. Does the foam help support sagging???
Also, one salesman encouraged me to have the chambers between the windows insulated as well; however, another told me that it wasn't necessary. Thoughts?
Thanks in advance!