Moving the Ducts Inside

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Moving the Ducts Inside

• Specifications Discussion

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Specs Summary (for discussion)

• Purpose Reduce duct system energy losses by
  designing the duct system to be entirely within
  the conditioned space.
• Methods Dropped Ceilings, Cathedralized Attics,
  Attic Plenums
• House Requirements
• Only new homes qualify
• Houses built on basements do not qualify
• Houses on crawlspaces qualify
• Houses built on slabs qualify
• Duct System Requirements
• Air-handler and all ducts must be within the
  continuous thermal and air barriers of the house.
• The crawlspace cannot be located within the
  thermal/air barrier of the house and ducts
• Duct joints should be mechanically fastened (not
  with tape) and sealed with mastic.
• No duct tightness testing is required.
• Unducted building cavities shall not be used to
  transport air.
• Ducts shall not be installed within exterior wall
  cavities.
• Inspection Requirements
• In-progress inspection required where ducts are
  within a soffit. Inspection ensures continuous
  air barrier is in place between the ducts and the
  unheated space.