ducted or free return air in foamed attic

I live in central Texas an am building a house. The roof as well as the walls will have foam insulation. My A/C contractor has two options for return air. One, to have grills in the ceiling to return the air to the air handler and two, to duct the return air. My concern with the grills is noise transmission between rooms. The contractor also says that this method will keep the attic within 10 deg of the home and reduce humidity. The ducted system should also make the attic cool but not as much. I worry in a humid climate that the attic will be humid. Would it be possible to have the contractor put a discharge vent in the attic to help remove humidity? Any comments or corrections to my assumptions would be greatly appreciated.

Thank you in advance

I would want the return ducted, preferably from every room except kitchen and baths. I would also recommend a supply register in the attic to keep the attic semi conditioned.

i would not want air pulled free from the house into the attic. The attic should be sealed with the spray foam but if they miss a spot it would allow a lot of hot humid air to be pulled in the house by the system.

An air tight foam structure with occupants needs mechanical fresh air ventilating during calm weather. Most suggest a filtered fresh air change in 3-4 hours to purge indoor pollutants and renew oxygen when occupied. Also critical is that you maintain <50%RH throughout the home to avoid growing mold or dust mites and maintain comfort during low sensible cooling loads with high outdoor dew points.

A well setup a/c will remove the moisture from the fresh air during significant sensible cooling loads. But as the sensible cooling loads decline during evenings and rainy days during common high outdoor dew points, the home will require supplemental dehumidification to maintain <50%RH. Many adding a small whole house dehumidifier with the filtered fresh air option to keep the humidity <50%RH throughout their homes.

Glad to see that you are concerned spaces in the home being humid. I suggest that you incorporate a unit like the SAnta Fa Ultra/Broan/Trane sized to remove moisture from the occupants and mechanical fresh air for occupants and exhaust device (clothes drier, kitchen, and bathroom exhaust).
Your thoughts?

Regards Teddy Bear

Ive done an open return on 3 occassions.

All 3 times were for cabins out in the woods, where there is no inspectors, and the owner is used to having window units and electric space heaters to heat there home.

When i explained how his heat pump worked, its like i was explaining a cell phone to a person in the middle ages.

Are you one of those people?

If not, ducted.