Frequently Asked Questions about Home Energy Ratings

What is a HERS Rater?

First of all, HERS is the acronym of Home Energy Rating System.  A HERS Rater is a specially trained and state certified third party testing inspector that verifies that applicable Title- 24 Standards are complied with.  A HERS Rater can hold several levels of HERS Certifications.  These certifications include:

  • HERS I,
  • New Construction,
  • Alterations and Non-Residential;
  • Solar;
  • HERS II,
  • Whole House Energy rating and auditing for existing homes and Energy Star v.3/Special Energy Programs certification. 

When do I need a HERS Rater? 

The California Energy Commission (CEC) requires that HERS Raters be used to verify Compliance to certain regulations in the 2008 Title-24 Energy Standards. Some of the mandatory regulations requiring HERS Field Verification and Diagnostic Testing (FV/DT) are:

  • Duct Pressure Testing and
  • Refrigerant Charge & Airflow Testing (RCA). 
  • A building permit is required before the work begins when a homeowner intends to either:
    • install a new (cut-in) HVAC system, or
    • change out an existing HVAC system.

Additionally, before the building permit can be finalized a HERS Rater must, under most circumstances, perform a Certified Duct Test and RCA. What tests are needed depend on the type of HVAC system is being installed, i.e.: “split system” or “package” unit.  

All new residential construction will require HERS FV/DT.  The type of FV/DT depends on whether the house is designed by "Prescriptive” or “Performance” approach and what the Title-24 specifications are called for by the Energy Consultant.

See also this letter from the CEC about duct sealing when installing or replacing central HVAC, and making sure your contractor obtains the proper permits.

CEC_070610.pdf | 24k Acrobat PDF

Under what authority does a HERS Rater work?

All HERS Raters work under the authority of the California Energy Commission through organizations called “Providers”. Providers train and certify HERS Raters and also provide the authorized registry that all HERS documentation and reporting is filed in. Building Energy Services & Technology is a CalCERTS certified HERS Rater. HERS Raters also reports to the local building department(s).

Who hires a HERS Rater?

HERS Raters are independent, third-party inspectors and are hired by Developers, Builders and Home Owners. 

HERS Raters can also work through an installing contractor but cannot work for said contractor.  Working for an installing contractor creates potential “conflict of interests.”  However, the state does allow installing contractors to hire and schedule a HERS Rater on behalf of the homeowner.  This is allowed to expedite the inspection process primarily because the typical homeowner does not know what the HERS Rating process is.  It must be understood that the HERS Rater is an “independent” inspector and is responsible to the Provider and the CEC.

Where can I find more information about the Title-24 regulations and HERS requirements?

Call the CEC at (916) 654-4287 or visit the CEC online at  The CEC offers an online downloadable HERS Booklet free of charge.