In the past I removed the screen and replaced it with a piece of plywood where i glued the thickest pink rigid foam insulation that would fit in the gap. After it was in place, I sealed it with spray foam from the inside. If nobody was going to see it I would do it again from the outside. But I am minimally handy.
anent_life t1_j02ia7a wrote
Reply to Advice request for best insulation for unique window situation by Clear_Lingonberry22
In the past I removed the screen and replaced it with a piece of plywood where i glued the thickest pink rigid foam insulation that would fit in the gap. After it was in place, I sealed it with spray foam from the inside. If nobody was going to see it I would do it again from the outside. But I am minimally handy.