When building a new home,

you will need to understand the new Home Energy Rating System (HERS) Program, the new standards and requirements associated with these changes. You will also need to work from the onset very closely with a HERS rater.

The HERS Program was initially implemented to address construction defects and equipment installations that had historically not been done correctly. These HERS measures cover HVAC system and insulation installation.
In an update to the HERS Regulations, the rating of a home as a system (known as Whole House Home Energy Rating) was implemented, where a home is rated on a scale from 0 to 250 to show its efficiency relative to a reference home built to just meet the Title 24 Building Energy Efficiency Standards' prescriptive requirements.

For more information about the HERS Program contact Energy Hotline http://www.energy.ca.gov/efficiency/contacts.html