I already learned from reading other posts my return grills are too small.
How do I calculate if the return ducts are too small, too?
I have a three ton downflow furnace a/c. I have two return ducts, hard metal round, one 14 inch and one 12 inch. How many square inches do I need to get the right airflow for 3 tons?
Both returns are above the ceiling, with lengths of 12 and 8 feet, two ninety bends, (one up, one down).
I want to find out if I need to tell whichever HVAC company I hire to replace my AC to just replace the return grills, or add another vent. I have not yet found anyone I trust to tell me what to do.