The issue with house service and convenience features, other than outside-wall windows and doors, is to not miss opportunity to save some energy, and to not allow conditions that rot. Think of a circuit breaker panel set into an outside wall. It is a blind penetration that won't let in any life-giving light. Therefore the minimum associated weatherization is air-tightness, and total R5 for that area of the wall, to be achieved outside the panel. It stays clean and dry, at near the temperature of the conditioned space. There is a vapor barrier, that is beneficial wherever you live. In Louisiana, or Port Aransas, Texas, humid outside air is not condensing under influence of your AC. In Barrow, Alaska, the space is not below the dew point in coldest winter, and sucking down the consequences of a little household health-giving humidity.
In keeping with this intelligent diligence, I am allowed, even openly encouraged, to stop at R5 as I construct and sell attic and crawl space portals. Yes, they are air-tight. They further stop passage of humidity. No plop-batt sops. Not the site-build failure I found in a wonderful state-park cabin floor. (Please see A Failed Floor Portal, among pdf Offerings, at my web page