I have wood double hung windows that have a cross shaped kerf seal. The kerf is about 1/8" and the flange that seals is about 3/16".
I haven't seen any similar seals anywhere online, except maybe brush seals. However I've heard that brush seals are not air tight, and I have 35 of these windows so bad drafts are a non-starter. Could you recommend anything for me?
Please and thank you.