According to DOE 's Builders Challenge program: ducts to be within buldings - Thermal / Air barrier

Hopefully there is are exceptions  for ventilation ducts!  The outside air inlet and outlet of the HRV/ERV  must cross the primary air barrier!   Also any bath fan vent duct, range hood duct and dryer vent duct.

Exceptions to locating 100% of forced-air ducts in home’s thermal and air barrier boundary are: a. Up to 10’ of total duct length is permitted to be outside of the home’s thermal and air barrier boundary. b. Ducts are located in an unvented attic, regardless of whether this space is conditioned with a supply register c. Ducts are located in a vented attic with all of the following characteristics: minimum R-8 duct insulation with an additional minimum 1.5” of closed-cell spray foam insulation encapsulating the ducts; total duct leakage ≤ 3 CFM25 per 100 ft2 of conditioned floor area; and ductwork buried under at least 2” of blown-in insulation d. Jump ducts which do not directly deliver conditioned air from the HVAC unit may be located in attics if all joints, including boot-to-drywall, are fully air sealed with mastic or foam, and the jump duct is fully buried under the attic insulation. e. Ducts are located within an unvented crawl space

Posted By Liebler on 23 May 2012 03:00 PM
Hopefully there is are exceptions  for ventilation ducts!  The outside air inlet and outlet of the HRV/ERV  must cross the primary air barrier!   Also any bath fan vent duct, range hood duct and dryer vent duct.

Exhaust ducting doesn't apply though should be insulated and buried under attic insulation to avoid condensation issues.