Skip to main content

Correct Installation of a Downdraft Ventilation

Checking the Installation for your Jenn-Air Downdraft Vent

Cooktop with downdraft

What is the length of the vent system?

  • To provide efficient performance, the length of the vent system and the number of elbows should be kept to a minimum. 
  • The maximum equivalent length of the vent system is 60 ft (18.3 m). For specific information, refer to your appliance's installation instructions.
  • For best performance at altitudes above 4,500 ft (1372 m), reduce the recommended vent run by 20%.

Was the correct vent material used?

  • Use a 26-gauge minimum galvanized vent or a 25-gauge minimum aluminum metal vent.
  • Poor-quality pipe fittings can reduce airflow.
  • A flexible metal vent is not recommended. 
  • Metal ducts may be reduced to 30-gauge galvanized steel or 26-gauge aluminized steel if allowed by local codes. This reduction is based on information in the International Residential Codes Section M1601.1 (2006 edition).

NOTE: Local codes may require a heavier gauge material.

How many elbows were used?  

  • Use no more than three 90° elbows.
  • Do not install two elbows together. If more than one elbow is used, ensure there is a minimum of 18" (45.7 cm) of straight vent between them. Elbows too close together can cause excess turbulence that reduces airflow.
  • If an elbow is used, install it as far away as possible from the hood’s vent motor exhaust opening.
  • Do not use a 5" (12.7 cm) elbow in a 6" (15.2 cm) or 3¼" x 10" (8.3 cm x 25.4 cm) system.

Other Recommendations:

  • Do not reduce to a 5" (12.7 cm) system after using 6" (15.2 cm) or 3¼" x 10" (8.3 cm x 25.4 cm) fittings.
  • Avoid forming handmade crimps. Handmade crimps may restrict airflow.
  • Use a vent cap for proper performance. If an alternate wall or roof cap is used, be certain the cap size is not reduced and that it has a back draft damper.
  • Use vent clamps to seal all joints in the vent system.
  • Use caulking to seal the exterior wall or roof opening around the cap.

If you would like to download or view product literature for your appliance, please visit our Manuals and Literature page.