HERS® Carbon Index


First-of-its-kind carbon rating index addresses the critical issue of greenhouse gas emissions

Climate change is becoming an increasing concern. The private sector, individuals, and state, local, and federal governments are seeking to combat climate change by reducing greenhouse gas emissions. In the U.S. it is estimated some 35 percent of these greenhouse gas emissions result from burning fossil fuels to power, heat, and cool buildings. Decarbonization of our buildings is critical if we hope to meet the climate goal of reducing U.S. emissions by well over half by 2030

The HERS® Carbon Index provides a more accurate metric to measure emissions: addresses when energy is used in a home, as well as how much can be reduced.

A RESNET® accredited HERS software program will take the information entered for a HERS Rating and calculate the Carbon Rating Index Score. No additional inspections are needed.

ANSI/RESNET/ICC 301 2022 Addendum B CO2e Rating Index

This ANSI standard was developed in cooperation with the Natural Resources Defense Council (NRDC), the Consortium for Energy Efficiency (CEE), the California Energy Commission (CEC), and the National Renewable Energy Laboratory (NREL).

HERS® Carbon Index Infographic

Link to Download Infographic

How Does It Work

  • Uses hourly CO2e emission rates and electricity generation emission projections as published by the National Renewable Energy Laboratory (NREL).
  • Combines these values with the hourly energy consumption given by the calculation of the HERS Index to provide a new metric valuing the carbon emissions when energy is used.

How Can It Be Used

  • Usable for local, state, and national climate change initiatives
  • Utility residential load-shifting programs
  • Utility incentive programs
  • Consumer awareness; to factor decarbonization into the decision to purchase or upgrade a home
  • In Environmental, Social and Governance (ESG) reporting
  • As a basis for green bonds