The easy way to field "drill" holes in SIP panels is to carefully orient the panel so that the would be hole is vertical propping the panel up a couple of inches off the ground, then drop a heated 1 inch diameter steel ball into the foam core. The ball melts a nice smooth hole straight down. Note that SIP panels typically have horizontal holes at 18 and 48 inches above the floor and vertically every 4 feet already. A contractor friendly (and cheaper) alternate to SIP is blown foam/fiberglass staggered stud walls (foam blown against outside sheathing). Wiring is a breese (no drilling). And the walls can be a thick (insulated) as you want (makes great sound barriers too).
Didn't mean to get personal about tubes.
I've done a lot of thinking/reading about energy efficient homes, everything from underground variations to foam igloos to passive/active solar to microhomes.
Mini-splits (air to air heat exchangers) get my vote for heating/cooling in many parts of the country and cooling everywhere. They're efficient and can be individually controlled. But up here in the great white north, we need another (primary) heat source.
What I don't like about in-wall speakers is image depth and inflexibility (can't move listening spot or take them with you and harder to swap out). Rear/side HT channels is another story, those rooms (like mine) is pretty much a fixed setup (one good wall for viewing) and their contribution is rather minor (speaking as an audiophile, not HT fan).
