West Central Florida; @1200 sq. ft. conditioned space w/only 7' 4" ceilings, ranch, block construction, small attic, low pitch, currently fair(maybe) ceiling insulation, walls likely none. Air handler in attic. Original central return air grill in wall 18 x24 leading to ductboard path "under" supply plenum leading to 14" flex to return. (about 6 turns?) 2 1/2 ton unit can't keep up on the scorching sunny days. In process of eliminating wall grill and putting in ceiling with 14" flex directly to air handler. Also sealing, radiant barrier, shading window, and will be further insulating, but insulation must be last b/c I won't be able to access after.
I realize this may only be a step at improvement, but was wondering if more return air is needed.
Thanks for any reply.