Are your window screen panels secure enough that you are confident enough to leave the house with the windows open? You especially need to ask yourself this if you live above the first floor. If your cat is at all capable of knocking the screen panel out of the window, catastrophe could happen. My screen panels are supposed to be secure, but they are not, so I secured them myself. I cleaned the window sill. Then I used packing tape. Some of the pieces went from the bottom of the outside of the panel to the window sill. Then I covered the pieces on the window sill with a lot more packing tape. Believe me, those panels are secure now.