We have loverly wooden sash windows, when we brought the house they were drafty and replacement sash’s were out of the question, so I brought draft proofing kits and myself and a retired master chippy set about fitting them, they work well, I also bung up the hole where the rope comes through as at certain times the wind blows through them, I also silicone sealed on the outside around the sash boxes where they meet the brick work.
Good luck.
Good luck.