Add 2nd return to system to improve airflow to system and to extend life of unit. Current return undersized for unit and home. Would need to enlarge 16†duct to an 18†duct. And adding an 18†adjustable 90, as well as a 18-16-16 wye. Then connect the old 16†duct and a new 16†duct as well as 14-30 return filter grill and can. 650 original bid 572 Total 1222$ Emailed new estiment to client