Here are some piquant comments from John Straube, Ph.D., a professor of building science and principal of the Building Science Corporation. BSC is presently working with the Passive House Institute of the US (PHIUS) to develop energy performance standards and methodologies for residential buildings.
The energy cost for a decent size IRC 2012 or EnergyStar v3 house is so modest, it is really hard to get any payback of almost any energy investment. People buy $4 latte’s so they are hardly motivated by reducing the monthly energy bill from $120 to $100 by spending 10K on, say, good windows. I have had a lot more success selling airtightness, windows, and insulation on the basis of improved comfort, health, disaster resilience, less dust indoors, and quiet, than I have had on direct payback. Energy is cheap, and we are building new houses that are not expensive to run if you follow even modest energy standards.