HVAC Folks: VAV Boxes

Factual Questions
1

What are the advantages to Variable Air Volume boxes? And, why choose a VAV over a Constant Air Volume box?

For VAVs specifically, I can see where there’s an advantage in that each VAV box has a separate control offering more individual control without the need for separate zones. In this fashion, VAVs can satisfy variable cooling needs (simply by adjusting the air flow) without the need for a larger air handler and/or cooling unit. And with this, the costs of the equipment are less, too.

Any other advantages to VAVs?
Thanks,

  • Jinx
2

Oops! Maybe the second question should be "Why choose a Constant Air Volume box over a VAV? It seems VAVs have more to offer, but maybe Constant Air Volume boxes are cheaper? But then, how is a Constant Air Volume box any different than just a run of duct direct to grille? What does a Constant Air Volume box gain you…perhaps the help of the option of a reheat coil, if the option is present?

A little confused,

  • Jinx