Please excuse the lack of proper terminology, I’m really not sure of proper terms. I’m trying to help my parents make energy improvements to their mid-1990s home. Checking windows around the house, I’ve found it’s very drafty around the sills. In most of the windows, there is only a plastic sill, but a few have some old “rubber gasket thing” that appears to have disintegrated elsewhere.
Based on the above, these are my questions:
What is this stuff called?
How much will it help with saving energy?
Any tips for properly installing it?