I look at things similar to AK. When we got hit with the hail storm back in 2011, we went back with some foam insulation under our new siding. Don't recall the R value. We also went with a gray metal roof to reflect the heat load in the summer. It seems to have helped. When we built we went with 2x6 framing and loaded as much insulation as it would take. I'd rather spend a dollar on something I want instead of funding the power company.