The U.S. Department of Energy (DOE) has formally adopted the Home Energy Rating System Index (HERS) and the use of HERS Index scores for homes that qualify as a DOE Challenge Home. The HERS Index will replace DOE's E-Scale and all DOE Challenge Homes will now be issued a certificate containing that home's HERS Index score. Formerly known as the Builders Challenge program, DOE Challenge Home requirements also stipulate that an energy rating by a certified HERS Rater must first take place in order for a home to qualify as a DOE Challenge Home. Based on its performance during the energy rating, the home is then awarded a HERS Index score.

The HERS Index, developed by the Residential Energy Services Network (RESNET), is a nationally recognized system for measuring and calculating a home's energy performance. The lower a home's HERS Index score is, the more energy efficient it is. A typical new home that conforms to current energy standards scores 100 on the HERS Index and is the baseline against which other homes are compared to for energy efficiency.

This move by DOE follows the direction set earlier by the Environmental Protection Agency, whose ENERGY STAR for Homes program also issues certificates with HERS Index scores to homes qualifying for their program.