The Question: Is our Return Air sized correctly? We run a 12Seer, 4 ton AC/Heat Pump. We have ONE 20X20 Filter which fits directly to the bottom of the unit. We have one vent opening feeding the unit which measures 13X 29 (377sq in)
We were led to believe that you need roughly 800sq in return air opening to feed 4 tons, so we were told to add another return air opening of about 450 sq in. Which we can easilly do BUT. How on earth would this change the air getting through the 20X20 filter?
My thinking is to configure EACH of the return air openings with it's own filter and remove the 20X20. Am I wrong here? None of the HVAC guys would comment.
Any help much appreciated, G