This seems like a broad topic and can be hard to understand real value. We are HERS Raters. That means we can quantify how much of a projected savings you'll get from selecting one building strategy or product over another. We have constructed different types of wall assemblies associated with energy efficiency. Insulated Concrete Form (ICF) wall, basement, and foundations, rigid and spray in place wall insulation systems, advanced framing, conditioned crawlspaces, wall and roof assemblies constructed with thermal and vapor breaks, and overall detailing during construction that deters moisture and thermal transfer from non-conditioned spaces to conditioned spaces and vice versa. We have LEED project experience and have LEED, Earthcraft Builder, Energy Key, and HERS training.