The HERS or Home Energy Rating System is a scale from 150-0. A score of '150' represents an older, inefficient home with high utility bills and a '0' represents a "zero energy" home that is so efficient it has no utility bills. The lower the score, the less energy your home will consume and the cheaper your energy bills will be.
Note that this score is a typical score for this specific floor plan – the score of a different home of this same floor plan may differ depending on several factors such as location, site conditions, and orientation of home.