Do’s & Don’ts

DON'T reduce the duct size

Just a 1" reduction in diameter impacts performance by 32% (or more)!

  • A 5" duct (in place of 6") will reduce 300cfm air flow to 205cfm
  • A 7" duct (in place of 8") will reduce 600cfm air flow to 400cfm.

DON'T use flexible ductwork

The ribbing creates resistance to air flow which:

  • Reduces efficiency/performance
  • Increases noise

DON'T turn sharp corners, & no "dead ends"

Vent-A-Hood® range hoods move air much faster than your heating/cooling system, therefore different ducting principles must be applied

  • Think of the heating/cooling system as a slow and steady water stream, finding its way over pebbles and between boulders.
  • The rapid airflow of a Vent-A-Hood® is more like water flowing through a garden hose; sharp turns and kinks in the hose will greatly affect, or even stop, the flow of water.

DON'T use plenum boxes

DON'T dead-end to back-vent

DON'T reduce duct size: TWO 8" ducts should not be reduced to ONE 8" duct

DON'T turn sharp or reduce duct size

DON'T dead-end or restrict airflow at exit

DO use VP562/VP563 transitions for 900/1200 CFM wall mount hoods

DO use VP561 Back/Side Vent Elbow

DO use VP563 transition for 1200 CFM wall mount hoods: TWO 8" --> ONE 12"

DO use VP561 Back/Side Vent Elbow

DO use Vent-A-Hood roof jacks that allow for free, continuous airflow.

DON'T use screens on wall caps or roof jacks - reduce airflow by 20-50%

DO use Vent-A-Hood wall caps and roof jacks with gravity dampers