When working with buyers looking for an energy-efficient single-family home, I've often had to cop to a bit of ignorance when it comes to Austin Energy's rating system of stars. What makes the difference between a 3-Star, 4-Star and 5-Star system had me puzzled.
That was before I found this handy (if a little dense) 65-page report on specific requirements and overall point values for the rating system. Here it is, in PDF form.
http://www.austinenergy.com/Energy%20Efficiency/Programs/Green%20Building/Participation/singleFamilyHomeRatingGuide.pdf