There are many construction and insulation approaches which allow a builder to create walls and ceilings with high R-values and low levels of air leakage, creating a much better envelope than is achieved with standard framing methods. Structural insulated panels (SIPs), insulated concrete forms (ICFs), double-stud walls, and advanced framing can all produce more energy-efficient buildings than the ol’ stick-built number.
The one thing they can’t do is to improve the efficiency of an existing house.
One of my first audit instructors stressed that we have to deal with the existing housing stock. People sometimes grouse that increasing fuel efficiency standards for cars is pointless, since cars last 5 to 10 years. Imagine how hard it is to improve the housing stock. Houses can last hundreds of years; moving that number is much harder.
As beautiful as all those building options are, they are only suitable for new construction. And