AC return vent size
Asked Apr 6, 2009, 10:44 PM
Maybe you can help me. My home has 2 zone heating/cooling. The AC units are 3 ton and 3.5 ton. I live in Arizona. Liquid lines were swapped out last year with 3/8" since 1/4" was the wrong size. The return vent hoses (1for each zone) are 16" round. The 3.5 has a 20x24 diffuser vent cover. The 3 ton has a 24" square one. I had readings on the 3 ton unit. He measured 575cfm. Would it help my efficiency to run an ADDITIONAL 12" flex return line to the air handler?