How can I seal old Jalousie windows?
Shrink film - works irrespective of window type. Apply doublestick tape around window frame, apply shrink film, heat with hairdryer or heat gun to shrink, remove in spring. Quite clear, quite effective, not very easy to remove/replace if you decide to open the windows in January, though it can be removed/replaced with care if you don't trim all the excess film when installing. "Shrink film window kit" will find a vast array in a search, or try your hardware store.