Moving Attic duct work to conditioned space to save energy. Return on Investment?
This house is in North Carolina, about 1800 square feet. Split 3 ton HVAC system with Gas Furnance. The attic is well vented with two power blower fans, but it still feels like an oven up there. I've asked a couple of HVAC professionals about moving my coil R6 duct work out of the attic into the conditioned space and they both kind of dismissed the idea, but everything I read online says it's one of the best energy efficiency improvements you can do.
the living room has a Cathedral ceiling so it wouldn't be that hard to drop the ceiling a little and get the main truck line into conditioned space.
In a totally DIFFERENT home which is around 1100 sqfeet we hired insulators to apply 8" thick fiberglass insulation and covered all the coil attic ducts. The ducts are now very cool. This document states 20% improvement.
Thoughts on why installers are telling me this is not worthwhile, yet everything I read says it is? Who's right?