Best type and location of air barrier
I’m in Zone 4A. I have seen much focus on using the interior drywall as the air barrier layer. This seems impractical, 1) air clearly flows easily in walls of homes here and that would essentially negate the value of the insulation, so stopping the flow (inside/outside) with drywall does little to stop the flow of heat & moisture with that air as it bypasses the insulation. 2) over the life of a home many penetrations to the drywall will occur and these will not likely be consistently sealed, ending your airtightness.
I’ve also seen the application of peel-and-stick membranes over the outside of the structure, with great added complexity of the framing sometimes required.
My feeling is that I should structurally sheath with OSB, add some exterior continuous insulation sheathing, then wrap the entire structure with 6mil Poly sheeting, paying particular attention to transitions between floor and slab, as well as floor to ceiling and floor to floor to maintain the air-barrier.
I’d add furring strips to the walls to attach siding and let the PE act as my water proof barrier also.
For the top floor, i’d run the PE under the truss bottom chord, add 2x below it for wiring chase and DW attachment, blow-in thick cellulose over it in the attic space.
This would put the PE in a durable location on the outside of the enclosure envelope and keep from introducing many punctures for every switch and light. I’d only have a few penetrations to deal with (like plumbing vent stack) and could take care with these.
This would require that all drying would occur to the inside of the house. House wrap is favored in this part of the country (Tyvek and Typar commonly), but while shedding water and passing vapor, these aren’t air barriers, right?