4.1 Ducts, flues, shafts, plumbing, piping, wiring, exhaust fans, & other penetrations to unconditioned space sealed, with blocking / flashing as needed.

See the following guides for relevant information.

Air Sealing Duct and Flue Shafts

Air Sealing Plumbing and Piping

Air Sealing Electrical Wiring

Air Sealing Bathroom and Kitchen Exhaust Fans

Air Sealing Light Tubes

Sealing Duct Boots to Floor or Drywall