Return Duct Takeoffs

[Gregory Morris]

I'm in the process of installing return ductwork for a new heat pump installation. I fully understand the reasoning behind keeping supply takeoffs 18"-24" from an end cap to allow the duct to pressurize and ensure even airflow at the takeoffs further upstream.

My question is simply, does this rule of thumb also apply to return takeoffs in individual room return systems? I can't imagine that it would, but I've found remarkably little discussing this.

 

[WorthFlorida]

For returns it's the square inches of the return grills and duct work. Too much restriction and there be poor air flow over the A/C coils or phelmun. Google "sizing return air duct" and there is plenty of information out there.