We say "tight," but you'll say 

"really, really comfortable."

Look around at the spec ("speculative") homes that typically go up. 2x4" walls with fiberglass batts, maybe open-cell foam if the homeowner-to-be is lucky.

Your wall is the start of all things good in your home and that means having the best materiel and techniques to limit air infiltration and ex-filtration.

We typically use structural insulated panels because it is the best combination of high-performance and economic-value. Integrated closed-cell foam limits moisture permeability while eliminating air gaps. The building minimum standard in Central Texas is R-13. At Texas Solar Homes, we look at R-42 systems.

When cooling and heating demand goes down, you live in a home that is comfortable, near-constant temperature, with the very lowest cost of ownership.