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Ventilation Hood Ductwork Recommendations


  • Must ductwork run vertical for Wolf Pro Wall Hood ventilation systems?
  • Is there a maximum recommended duct run?
  • Can elbows and transitions be placed back-to-back?
  • Can less than the recommended duct size be used?
  • Can flexible metal ducting be used?
  • What size ductwork to use for a Wolf blower motor?


Note that ductwork should be installed according to the recommendations of an HVAC expert. These resources supplement, and do not replace, the advice of an HVAC expert.

Wolf Ventilation hoods will operate most efficiently when ductwork does not exceed 50' in "equivalent" length (40' in "equivalent" length for downdrafts).

  • Ductwork can be routed in any direction from the hood transition.
  • A straight, short duct run with limited elbows and transitions will allow the hood or downdraft to work most efficiently.
  • Running ductwork down is fine as long as restrictions are adhered to (length, elbows, distance between elbows, etc.).
  • Municipality requirements may be more restrictive than Wolf's recommendations; refer to local code for specific information.

Duct Elbows

  • Do not place elbows and transitions back-to-back.
  • When possible, include a minimum 15" straight ducting between elbows and transitions.
  • 15" of straight ducting is also needed between blower and elbow.
  • Elbows and transitions placed too close to each other will cause a decrease in ventilation performance.

Duct Size and Type

  • Use recommended duct sizes.
  • Depending on the specific ventilation product, Wolf recommends 8" round or 10" round ducting.
  • Smaller duct sizes will significantly reduce ventilation performance.
  • Use of ducting other than recommended will not void warranty, but may compromise performance.
  • Do not use flexible metal ducting.
  • Flexible metal ducting will increase air resistance and is not recommended by the National Uniform Mechanical Code Standards.

See also:


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