They're used for both heating & cooling. With both at floor-level, for
heating, location is quite immaterial.
For cooling, for hopefully obvious reasons, distance is good. But,
not the only point of interest, if both are at same elevation. For
more evenly-distributed temps in a given space, you can get
louvers that can discharge in directions other than straight.
And, you can get external diverters (for lack of better word) that
attach with magnets and allow you, for instance, to direct
discharge up rather than straight out.
Are you experiencing a problem, or is this an academic pursuit?
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