Been doing a bunch of reading on here, but still am a bit confused on return duct size.
I have a 5 ton AC unit, and I have 3 return ducts throughout the house, the filter sizes are as follows:
Grills are slightly larger than the above filter sizes, so they fit in well.
It seems that the return size recommendation is between 144 and 200 square inches of return per cooling ton. My calculation appears to be 157.6 sq inches of surface area per ton. (500+144+144=788 /5)
I think my vents are somewhat loud, not howling, but very noticeable. I appear to be at the low end of the recommended size range, but they should be perfectly acceptable baring any duct problems right?