The key is proper duct system design, which falls short, in many cases. If merely installing a replacement system with new like material, the results may not be better.

In any case, dampers allow the system to be tweaked, enabling (usually) small changes in performance.

V

P.S., I'm not a PRO.
P.S. 2, Tiger, congrats on the *

I built with balancing dampers recently. I tweak them for my own perverse needs - the rooms were even before. We like to sleep in the cold so I damp the bedroom down in the winter and damp other things down in the summer. We have an Infinity system that won't let static pressure climb too much.

Building again without dampers because of the duct location. Not terribly concerned but I will come up with solutions to sleep cold. The ducts are all on the floor which makes it easier to cover and redirect flow (and I am having excess supply ducting).

So my vote is that I agree with vee. Except that rather large differences can be made with dampers.

Thanks for the feedback. This is a total redo. My old furnace is a downdraft, sitting in a closet, supply ducts in crawlspace, returns in attic. With the remodel, closet is gone, and all ducts must be in the attic -- no room for a chase.