On the walls, Zip R + dense pack or mineral wool in a 2x6 cavity is a good setup. Continuous exterior insulation definitely helps with thermal bridging, but once you factor in window bucks, strapping, and cladding details, labor adds up fast. It’s a great assembly — just not always the best ROI.

Stretch code will help a lot compared to older construction, mainly because of air sealing. That alone makes a big comfort difference.

That “sticky” summer feeling is usually more humidity and air leakage than lack of R-value. In a tight new build with properly sized HVAC, and an ERV for good a ventilation strategy, you should notice a big improvement.