The best item to look for is an overall rating or credential that the home might carry.
- Look on the electical service box and see if the home has a HERS rating.
- The lower the score the better the efficiency. An 85 rating is what you'd need for an EnergyStar home. This will tell you if the home has been tested and evaluated for energy usage.
- Also, the home might be LEED certified by the US Green Building Council.
These holistic programs offer the consumer big advantages. Today energy efficiency is big news, but more important is the clean indoor environment. The EPA has an Indoor airPLUS designation (also on electric service box) which says a whole lot about the durability of your home and how it will perform over time concerning clean indoor air.
In my opinion a little green feature here or there is not worth looking for.