Originally Posted by rleffler
Just add some weather seal to the back off the overhead to seal up against the bulkhead. Then install a couple 2" flanges in the bulkhead. You can get these from Spruce.
I used 2"x1" flanges since I didn't want to cut 2 2" holes in the baggage bulkhead. The airflow in the cabin with all 4 vents open is very good.